Receiver Options
It won't take much power to make things loud in your small room. I would recommend something in the $300 range like a Yamaha HTR-5960 or a similar model from Denon. If you get a bigger place in a couple years, you can upgrade to an HDMI model with the latest features, etc.
Not sure if you have the speakers picket out, but you might consider using your budget on a good 2 channel or 2.1 system and expanding as your room and budge allows.