c2q 9xxx is indeed your best and only valid upgrade path on that motherboard. It's a very capable cpu on par with the higher end phenom II's.
As you already found out, the problem is that every gamer with a c2duo (which is now downright shit for gaming) wants that cpu (since it's the only good upgrade), they are almost impossible to find second hand at a decent price and the retail price (the few places you can still find them) remained super high.
That cpu alone costs as much as an am3 amd mobo + a high end phenom II (of similar performance to that c2q), just to show how overly expensive that c2q cpu is.
The next step up (i5 2500k/3550k) combined with a new mobo will cost you almost 320 euros....(so double)
Welcome to a competitionless 2012, it sucks for everyone.
PS don't buy lower end amd cpus or the new FX ones, they are dogshit.
Source:
http://techreport.com/review/23246/i...ith-today-cpus
Those shitty overly hot bulldozer cpus deliver decent average framerates but are completely worthless for gaming because they provide inconsistent framerates. If you get 60 fps average but 10 percent of the frames take as long to update as an average of 20 fps would, then you still get stutter, so there is absolutely no point to buy these for gaming.