Ditto as above. You either need to run new speaker wire down to the TV area to place the speakers closer to the TV or go to in-ceiling, which are designed and angled to work that high. In ceilings are not the best way to go, but if you are trying to maintain aesthetics, they are great. You could even do in-wall in front if you wanted everything hidden, which would be better than in ceiling, but not as good as free-standing. If you are going to be placing your receiver on the front wall, just run new wire to some towers or wall-mounted speakers and either leave the brackets and wire up high, or patch and paint.
The 4 "crescent" speakers in back will work okay for surround until you can afford something better. There are several companies that offer good in-ceiling surround speakers. I have a friend who uses Atlantic Technologie's Tri-mode in his ceiling, and truthfully, the sound is amazing.