Converting USD$ to AUD$
 

I created a spreadsheet that shows Sales over a 24 month period. It is
currently in AUD (Australian Dollars). If one did not know it was in AUD, it
would be impossible to tell because the numbers just have a "$" next to them.

What I would like to try and do: I would like to create and drop down list
with two options. One for USD and one for AUD. When a user selects either
one, it automatically converts a specified range of cells (the cells with
money in them) to the respective currency using a user-defined exchange rate.

Is this possible?

Thanks!
Mike