RSS to show posts from previous week?

Is it possible to ammend the php for the rss feed, so that only posts from the previous week (Monday to Sunday) show up?

The plan is to use the feed to show ‘Last Weeks News’ so that it can be printed out for archive.

I would still need to ue the /?feed=rss2 original, but if I could somehow make a copy for the modified version e.g. /?feed=rss2a

Any ideas how I could acheive this would be greatly appreciated. It is quite important that I come up with a solution this week.

Thanks