You're right...the Galaxy is only good for vocal monitoring, but it does a good job for that. I use it and a non-powered Galaxy for our trio, with two singers.
In a pinch, I have used a Roland cube 30 guitar amp, which I think has the same specs as the monitor, but with one channel and built in effects. Not really very loud.
Often, I use a Peavy Minx with active eq. It has good range. I use a kick-back kind of stand. Mostly, I use this outside, since it's old, and if it gets damaged, is no big deal. Suprisingly, I like this better than the Galaxy and the Roland...better bass response and durable as a tank.
Russ