*Be aware there is an AWESOME deal going on with AMD where you can get THREE FREE GAMES with an HD7950/70.
Would the HD7950 be bottlenecked by your CPU? Yes and no. Yes it would NOT run as quickly as an i5-3570K for example but it varies by the game.
Yes (before I'm flamed), this is out of your price range but if you would be buying these games anyway (even for less money) then it's definitely worth investigating.http://www.scan.co.uk/products/3gb-xfx-radeon-hd-7950-double-d-5000mhz-gddr5-gpu-800mhz-dvi-dvi-hdmi-mdp
**The above card is an EXAMPLE. I prefer AMD/Sapphire usually. The price of the XFX is lower than most so you'd want to investigate that it isn't too noisy or has other issues. (In North America I was recommending one of the Sapphire or Gigabyte HD7950 cards with the THREE FREE GAMES packs. It depends what is available, plus reviews of the exact card for noise, reliability etc.)