Previous Quarter / Month Issue

Hi

We have a requirement in which we need to display the previous quarter calculations.

We have two prompts Year and Quarter , and we have Objects like Month , Current Month Count(count of profile_id), Previous Month Count(count of proifle id).

Now suppose user selects Year = 2007 and Quarter = Q1 , then the output should look like:

Month Current Month Count Previous Month Count

Jan 150 ?

Feb 250 150

March 350 250

The value for Jan ( Previous Month Count) is not coming properly.

As when we enter year = 2007 andquarter = Q1 , the data of December 2006 should come in the previous month count of Jan.

Can anyone suggest me how to solve the problem?