Or you can shell out £160 for an XFX HD 7870 like I did and play everything on max at at least 50+ FPS.
50-70 FPS on BF3 at Ultra is pretty fun :V, I could be getting way more but my CPU is bottlenecking my card a bit, I either need to buy a Piledriver or OC it to 3.8 Ghz+ and for the latter I need a new CPU cooler