Date Formula Problem

I am a complete noob with crystal reports and am in real trouble with monthly billing, so any help would be greatly appreciated.
our billing period is from 7/31 - 8/30, and the reports are run on 8/31. We found a bunch of mistakes and had them fixed but now I need to be able to rerun
the report for that time period today. All my time formulas are below, please help.

Report Date

"For the Month of " & ToText(CurrentDate - 15, "MMMM") & " " & ToText(CurrentDate - 365, "yyyy") & " & " & ToText(CurrentDate - 25, "yyyy")

Current Year

If {orders.DATE} in Maximum(LastFullMonth) to CurrentDate - 1 then 1

Previous Year

If {orders.DATE} in Maximum(LastFullMonth) - 365 to CurrentDate - 366 then 1That's the problem with using CurrentDate - it only works on the actual date!
Replace the use of CurrentDate with a formula. Make the formula return the date you want to simulate running for. Then you'll only ever need to change one thing in the report to get it to run for whatever date you like.
Or take it one step further and use a parameter so you don't even have to change the report. You could still use an intermediate formula so that you can make it work however you want without having to alter the report much at all.|||How would I go about setting it up to just use a specified date range, I tried using DateValue and for some reason it would always come up with the year 1898.