I don't see the low light performance of the 70D being THAT much better than the 60D. And I agree with what others say... to really see a difference, you have to go full frame. 5D mkii body you can find for around $1400 new, probably a bit cheaper used. I've seen a a 60D with a 18-135 lens for $900 recently (maybe less), which means around $600 for the body after you sell the lens. A new 70D will probably be around $1300 new with an 18-135 (which is roughly what the 60D cost at launch and shortly thereafter). So about $1000 for the 70D body.
If I were to talk about value, I think the 5D mkii is the best value between the three, the 60D being the next best, and finally 70D simply because it will be over priced initially.
As for AFMA, you can send in the camera and lenses to Canon and they will AMFA the body to your lenses. So there is that option.