From your post, this is what I gather your talking about-
#include
$oExcel = _ExcelBookNew()
$oExcel.VBE.ActiveVBProject.VBComponents.Import(@DesktopDir & "mymacro.bas")
$oExcel.Run("nameofmacrohere")
I tested this out, and it imports the bas file to a new workbook, and runs it.
EDIT to fix the code tags and... just letting you know, a lot of vb code can be pretty easily converted. It can help you when searching google for things, as you don't have to try to search for someone who has done it in autoit only for the vb equivalent.