VB / Excel for a Newbie

Im a Jr. Unix Admin / Web designer suddenly
required to generate reports in Excel - so please
be gentle in your responses...I've heared this is
simple.

We have an odbc driver which enables us to run a query against our TSM server to return historical
information (amounts backed up).
This returns B, KB, MB and GB values though...
I now need to convert all to Bytes.
I know I can search for MB / GB / KB but - my problem is how to tell it - if nnn.nn MB then X's by whatever and replace MB with Bytes.

Does this make sense?!