How to get current week using Calender control in asp.net

Hi
this is sathyam
I want current week date and month when i select a date using calendar contol.
like 
 i want display in textbox like dec 15-december 2008(*dec-current month,*15-date of current week firstday(monday)) when i select any of the date of that week.
and i want dispaly default date when u navigate months 
how can i do it????
please help me 
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