How much are you wanting to spend? With my band, I use that yamaha powered mixer I listed, 1 of the JBL JRX125's and a couple of floor monitors. We use it for vocals only. It works great! For garage band situations, there's no need at all to mic anything but the vocals. If your drummer is too loud, get him to use smaller/lighter sticks, and make him learn to play a little softer. Everybody has to make compromises in a band! If someone else is too loud, get them to turn down before you turn up, or you'll be having a continuous volume war. Everybody should set their volume according to the quitest person in the group.

I would probably suggest getting a non-powered mixer, a power amp, and 2 1x12" or 1x15" mains cabinets. This will get you by nicely for practice and your average gig. it will also leave you room to grow, and still use what you have.