Yeah people have become greedy with FPS these days, now that our mainstream GPU hardware far outruns the majority of PC releases' graphical quality these days...
People used to be happy as long as they remained above 30fps, now its 60, and I'll admit, now that I'm 6970x4 quadfire, my minimum is 120 because of my 120hz monitors. I can really notice the difference between 60fps and 120fps with the new monitors. However if I HAD to run on 1 GTX 560 Ti, I would just OC it to 1050mhz/2200mem and just enjoy the 40-50fps I'd get in the more demanding titles @ 1080p/4xAA.
I've got 2 GTX 560 TIs for sale for $175 shipped (Twin Frozr II) and $190 shipped (MSI Hawk)
Or if you're thinking 6950 2GB, I've got an ASUS Voltage Tweak Edition flashed to a 6970 for 210. I've pretty much got the rest of them sold (I think) but you never know.
Not trying to plug my FS thread here, just suggesting that you take a look at the For Sale section before you pay retail is all. I'm looking for someone to trade a GTX 580 for my 2 GTX 560 TIs, but if that falls through I'd just end up taking $350 for both of them or the prices I stated prior for each.
Good luck finding a card. I wouldn't suggest a 460 when a 560 Ti owns it and is barely any more $$ if you know where to look