If it were me, I'd use Python and xlrd/xlwt - http://www.python-excel.org/ , or save the XLS file as a CSV and write a script in an editor, but I don't know VBS so it's the hammer/nail problem.
Since you shouldn't be limited by what I know, ;-) , this may give you some VBS ideas - it sounds similar.
http://www.tek-tips....d.cfm?qid=1167426
HTH!
Cheers,
Scott.