Calculating receipts from previous month based on the sales of current mont

Hi Gurus,

I have a requirement where i need to display sales for a quarter and need to display receipts from the previous quarter. For example consider that i am displaying sales from week1-Aug to Week4-October, I need to display receipts ( R_Net_RCPTS) from Week1-july to Week4-September. In that way If i select Wk1-Aug for sales it should display Wk1-july receipts. i need to do this in Webi by creating appropriate variables.

I have got prompts on year and Fiscal Week

I have given year as 2011 and The "08: Fiscal Week From:" as "Wk1-Aug" to "08: Fiscal Week To:" as "Wk4-Oct"

I HAVE GONE THROUGH ALMOST ALL RELATED THREADS, BUT COULDN'T FIND ANY SOLUTION. ITS REALLY URGENT. PLEASE HELP ME AND I WILL FOR SURE GIFT POINTS.