Here's another suggestion. Get a decent stereo amp to drive your 2 main speakers, and use the rest of the 5 channels in your 2802 to drive the rest. Any decent stereo amp, even a cheap one, would probably have better sound quality than your 2802 receiver.
My advice is to look for the Onkyo 282 (I think that's model it was to power the Onkyo's two rear channels for their AVR), Adcom 535, or an Audiosource Amp 3 all can be found for a pretty cheap price.
Another place to look is at a pawnshop and buy one of the old classics (they may look old and ugly but most were made pretty good at the time) which should run less than $150 easily and sound better than most AVRs being used for those rear two channels.