In my experience, focus issues with an EOS camera that isn't obviously broken are usually due to the AF not doing what I expected, rather than to anything actually *wrong*.
If manual focus is off too, then maybe the mirror has gotten out of alignment so that the optical path lengths aren't quite right. But eliminate other variables first.
If I were you, I'd take the rest of that partial roll and do some controlled focus experiments with a measuring tape. Use a tripod, take pairs of shots using auto and manual, document where you attempted to focus, and see what the results look like. Do it with two lenses; maybe your 85mm is out of adjustment.
Tragically, or perhaps conveniently, the lower-end EOS bodies are basically being given away; I just looked at KEH and you can get a Rebel X for *five* *dollars*. It's probably more cost-effective to treat them as disposable than to repair them.
-NT