BEx Query Variables used in Design Studio

Hi Experts,

    My requirement is i want to add 2 variables(ie coming from BEx Query) with date range as input.

1-Date To Date

2-Week To Date

i want to add one radio button or check box type anything,where i select date range at a time either for Date to Date or Week To Date variable..

please pass the logic for refresh button if radio-button i am using for both the Variable...

if check box using whats the logic...

its urgent ...please help ASAP.....

FYI i'm using DS 1.3

Thanks in Advance

Ashwin.