To build muscle, you need to INCREASE your load. Doing the same weight over and over again isn't going to get you far. You may want to read up on progressive overload. en.wikipedia.org/wiki/Progressive_overload
I recently drew up a very simple beginner strength program that incorporates progressive overload. www.sparkpeople.com/mypage_public_journal_
Of course, it's going to require access to some free weights which doesn't fit your requirement of using 3 pounds, but I would warn you that your 3 pound weights will likely get you little or no results.
I would also recommend you talk to your doctor before starting any strength program.