Adding Source File Name to First Column of Workbook (VBA)

I'm fairly new to using VBA, but I currently have a code written that does the following:

• Searches within a folder, all excel files which contain a specific worksheet, and outputs in to a master sheet.

I am trying to add a column, either at the beginning or end of the master sheet which indicates the file source name. My code is the following

Sub CombineWorkbooks()

    'Declare the variables
    Dim arrFiles() As String
    Dim strPath As String
    Dim strFile As String
    Dim wkbDest As Workbook
    Dim wksDest As Worksheet
    Dim wkbSource As Workbook
    Dim wksSource As Worksheet
    Dim SourceRange As Range
    Dim SourceRowCount As Long
    Dim NextRow As Long
    Dim LastRow As Long
    Dim LastCol As Long
    Dim FileCnt As Long
    Dim Cnt As Long
    Dim i As Long
    Dim CalcMode As Long

    'Specify the path to the folder containing the files
    strPath = "FOLDER PATH\"'Make sure that the path ends in a backslash
    If Right(strPath, 1) <> "\" Then strPath = strPath & "\"'Check if the path exists
    If Len(Dir(strPath, vbDirectory)) = 0 Then
        MsgBox "The path to your folder does not exist.  Please check"& vbCrLf & _
            "the path, and try again!", vbExclamation
        Exit Sub
    End If

    'Get the first Excel file from the folder
    strFile = Dir(strPath & "*.xls", vbNormal)

    'Fill the array with a list of Excel files in the folder...
    FileCnt = 0
    Do While Len(strFile) > 0
        '...except this workbook, in case it's in the same folder
        If strFile <> ThisWorkbook.Name Then
            FileCnt = FileCnt + 1
            ReDim Preserve arrFiles(1 To FileCnt)
            arrFiles(FileCnt) = strFile
        End If
        'Get the next Excel file from the folder
        strFile = Dir
    Loop

    'If no Excel files were found, exit the sub
    If FileCnt = 0 Then
        MsgBox "No Excel files were found...", vbExclamation
        Exit Sub
    End If

    'Change the settings for Calculation, DisplayAlerts, EnableEvents,
    'and ScreenUpdating
    With Application
        CalcMode = .Calculation
        .Calculation = xlCalculationManual
        .DisplayAlerts = False
        .EnableEvents = False
        .ScreenUpdating = False
    End With

    'Create a new workbook with one worksheet
    Set wkbDest = Workbooks.Add(xlWBATWorksheet)

    'Set the destination worksheet
    Set wksDest = wkbDest.Worksheets(1)

    'Specify the row in which to start copying the data
    NextRow = 1

    'Loop through each Excel file in the array...
    Cnt = 0
    For i = LBound(arrFiles) To UBound(arrFiles)

        'Open the current file
        Set wkbSource = Workbooks.Open(strPath & arrFiles(i))

        'Set the source worksheet
        On Error Resume Next
        Set wksSource = wkbSource.Worksheets("Worksheet you are looking to import")
        On Error GoTo 0

        'Check if the worksheet exists
        If Not wksSource Is Nothing Then

            With wksSource

                'Find the last used row in Column A
                LastRow = .Cells(.Rows.Count, "A").End(xlUp).Row

                'Find the last used column in Row 1
                LastCol = .Cells(1, .Columns.Count).End(xlToLeft).Column

                'Check if the worksheet contains data beyond column headers
                If LastRow > 1 Then

                    'Increase the count by one
                    Cnt = Cnt + 1

                    'Set the source range...
                    If Cnt = 1 Then
                        '...including the column headers
                        Set SourceRange = .Range("A1", .Cells(LastRow, LastCol))
                    Else
                        '...excluding the column headers
                        Set SourceRange = .Range("A2", .Cells(LastRow, LastCol))
                    End If

                    'Count the number of rows in the source range
                    SourceRowCount = SourceRange.Rows.Count

                    'If there aren't enough rows in the destination sheet,
                    'exit the sub
                    If NextRow + SourceRowCount - 1 > wksDest.Rows.Count Then
                        MsgBox "Sorry, there are not enough rows available "& _
                            "in the destination worksheet!", vbExclamation
                        wkbSource.Close savechanges:=False
                        GoTo ExitSub
                    End If

                    'Copy the data from the source range to the destination sheet
                    SourceRange.Copy
                    With wksDest.Cells(NextRow, "A")
                        .PasteSpecial Paste:=xlPasteValues
                        .PasteSpecial Paste:=xlPasteFormats
                    End With

                    'Determine the next available row
                    NextRow = NextRow + SourceRowCount

                End If

            End With

            'Set the object variable for the source worksheet to Nothing
            Set wksSource = Nothing

        End If

        'Close the current file, without saving it
        wkbSource.Close savechanges:=False

    Next i

    'Check if any data has been copied to the destination worksheet
    If Cnt > 0 Then

        'Select the first cell and change the width of the columns to
        'achieve the best fit
        With wksDest
            .Cells(1).Select
            .Columns.AutoFit
        End With

    Else

        'Display message box advising user that no data was available to be copied
        MsgBox "No data was available to be copied...", vbInformation

        'Close the destination workbook, without saving it
        wkbDest.Close savechanges:=False

    End If



ExitSub:

    'Restore the settings for Calculation, DisplayAlerts, EnableEvents,
    'and ScreenUpdating
    With Application
        .Calculation = CalcMode
        .DisplayAlerts = True
        .EnableEvents = True
        .ScreenUpdating = True
    End With

End Sub

Any help would be greatly appreciated!