Probelm in calculating formula in excel vba

Hi,
I have a access report that exports to excel with click of a button after choosing parameters. This works well. However I have to modify couple of fields to utilize formula in the export module. I am not sure how to do this. I am writing the above code which seems to cause problem. I appreciate any help to resolve this issue. Thanks.

If lngColumn = 12 Then
  xlc.Offset(0, lngColumn).Value = =([UnitPrice]*[OriginalShippedQty])/1000
End If

If you need to put VBA code in Ms Access and your Excel file is closed I think you need something as this:

Dim xl As Object
Dim ws As Worksheet

Set xl = CreateObject("excel.application")
xl.Workbooks.Open FileName:="c:\<file name>.xls"
Set ws = xl.ActiveWorkbook.ActiveSheet
'here put your formula, i.e.:
ws.range("a1").formula = "=sum(a2:a100)"
'save file
xl.ActiveWorkbook.Close True
xl.Quit
Set xl = Nothing

Regards,
Antonio

Thanks Antonio for your help. Actually I am writing the vba in the access vba and using a query to loop through the query and output the values in excel file. My problem is exporting formula to excel. The formula example is something I have provided.