How to display the Line Graph week wise with using one parameterise Date?

Hi,

How to display the Line Graph week wise with using one parameterise Date?

End User wants to display dates on x axis and its values on Y axis .

i.e. if we choose 1/10/2012 then on x axis we have to display 1/10/2012 7/10/2012 14/10/2012 21/10/2012 28/10/2012 31/10/2012

suppose i select 1 parameter startdate then other week date will startdate+7 next date will (startdate+7)+7 & next ((startdate+7)+7)+7

Please help me any one have idea.

Thanks

Nilesh Pawar