Manipulate dates by week

Hello to all,
I don't now if this is the right forum.
I work with Gregorian Calendar to work with dates and time, but now i'm having a problem.

At this moment i have to show results where a user select a week and a year
and the return has to be the days of that week (Monday and Friday)

EX:

Week 36 of 2009:

I want the Monday day of week 36 (31-08-2009) and Friday day of week 36 (04-09-2009) .

Does anybody nows how to do it?

Thanks in advanced,
Nuno

The Calendar#add method will have what you want. Look at the Calendar API for details.