Hola, mira si te vale este ejemplo
Código:
Dim oExcel As Excel.Application
Dim xLibro As Excel.Workbook
Dim xHoja As Excel.Worksheet
Dim Columnas As Integer, Filas As Integer
Set oExcel = CreateObject("Excel.Application")
Set xLibro = oExcel.Workbooks.Open(App.Path & "\Libro1.xls")
Set xHoja = xLibro.Sheets(1)
Columnas = xHoja.Rows(1).Find("").Column
Filas = xHoja.Columns(1).Find("").Row
