Not the cleanest code in the world but I think you will get the idea...

Imports Excel = Microsoft.Office.Interop.Excel
Imports System.IO
Imports Microsoft.VisualBasic
Imports Microsoft.Office.Interop.Excel
Imports Microsoft.Office.Interop.Excel.XlColumnDataType


Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim xlApp As Excel.Application
        Dim xlWorkbook As Excel.Workbook
        Dim xlWorksheet As Excel.Worksheet
        Dim myStr As String
        Dim FileReader As StreamReader
        Dim FileWriter As StreamWriter
        Dim results As DialogResult
        Dim openFileDialog1 As New OpenFileDialog()
        Dim mycol(,) As Object = New Object(,) {{1, 2}, {2, 2}, {3, 5}, {4, 1}, {5, 2}, {6, 1}}

        openFileDialog1.InitialDirectory = "c:\"
        openFileDialog1.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*"
        openFileDialog1.FilterIndex = 2
        openFileDialog1.RestoreDirectory = True
        results = openFileDialog1.ShowDialog

        If results = DialogResult.OK Then

            FileReader = New StreamReader(openFileDialog1.FileName)

            myStr = FileReader.ReadToEnd()
            'myStr = Replace(myStr, "'", "")

            FileWriter = New StreamWriter("c:\Temp\invoices.txt")

            FileWriter.Write(myStr)

            FileWriter.Close()
            FileReader.Close()

            xlApp = CreateObject("Excel.Application")

            xlApp.Visible = False

            xlApp.Workbooks.OpenText("C:\Temp\invoices.txt", , , , XlTextQualifier.xlTextQualifierSingleQuote, True, FieldInfo:=mycol)
            xlWorkbook = xlApp.ActiveWorkbook
            xlWorksheet = xlWorkbook.Worksheets("invoices")

            MsgBox(xlWorksheet.Cells(2, 1).value)
            xlWorkbook.SaveAs("c:\Temp\invoices.xlsx", FileFormat:=51)
            xlWorkbook.Close()
            xlApp.Quit()
            releaseObject(xlApp)
            releaseObject(xlWorkbook)
            releaseObject(xlWorksheet)
        End If

    End Sub