The Sioux is my favorite air drill (I have several brands) - small and light with good trigger control. If you're not going to be taking out that many rivets, then pretty much any drill will do, but I recommend you get yourself a rivet removal tool -
http://www.yardstore.com/browse.cfm/4,4332.html . With it, pretty much any drill will work and it'll center the bit on the rivet. It'll set the depth too. I use a small light varible speed lithium-ion cordless drill lots for removing rivets, so what you have should work fine.