This is the result of the way that field references work within Microsoft Access. If you would like to use a formatted value within a Field Reference in Total Access Emailer, simply use a query for the data source and add a calculated field with the value to use.
Expr1: Format([CurrencyField], "Currency").
You can rename "Expr1" to a more meaningful name if you would like, then reference that field within the email as a Field Reference.
Check to make certain that you have the Use Field References option selected in the interface.