Crystal Reports Formula Help

Message

   I have a query in SQL 2005 that I want to convert to a formula. Here is my query:
declare @todays as datetime

set @todays ='02/15/2010'

select DatePayment , sum(dollarsunallocated)

from VWr_Insurance_Payment

where dollarsunallocated >0

and datepayment >= (@todays -30)

group by datepayment,payorname

I created this formula
if date ({TPr_InsPayments;1.DatePayment}) in {?@todate} - {?Period A} to {?@todate}
then Sum ({TPr_InsPayments;1.DollarsUnallocated},{@Group - Payor Name} )
else 0 

but it is not working correctly

can anyone help me with this?