PLEASE help with this Crystal Reports problem!

Hi there

I need to produce an invoice as part of a huge program. The problem is, the client want to select the user,
and then the month for which the invoice must be printed and then the invoice must be produced,
getting data from the db. The only option i thought of, was crystal reports...
but i cant seem to find anything there about having the option the enter the data and THEN produce the one
report about it...

Please help, it is quite urgent.. Working with VB.Net and Access 2003..

Thanks