Text Variable with Outcome showing actual and previous Jahr result

Hi Experts,

i am working on report and would like to implemet the following.

I have create a report which is using a text variable.

I would like:

to select Last year Date for (12.2008) -

> Onbtain Result for 2008 but publishing in the Column header the actual date (01.2009).

How could i realize it?

Thank you for your Input.

Pat