Recommend some surround speakers.

[Riff Magnum]

I have Klipsch RF-35's for fronts and a klipsch RC-62 center channel speaker. I have yet to upgrade my receiver, but it's useless since it only has "simulated" surround sound, no 5.1, and no hdmi. Anyways, i need 4 speakers to round out the 7.1 setup (once i have a sub). I want them to be really good and really small, since i'm probably gonna mount them at the top of my wall right before it meets the ceiling and just angle them down towards the listening area. On a semi-related note, should the side surrounds be at a direct 180 degree angle from the listening position? Should the back surrounds be directly behind the main listening position? I'd like to keep under $1000.