bf3's recommended gfx req. is radeon hd 6950, so you'll need that or higher to play bf3 at high detail and resolution. imo the gtx 560 won't be fully using its 2gb ram - not worth the extra cost.
single card - gtx 570 or radeon hd6970
multi card - 6950 cf or gtx 560 or gtx 560ti sli
radeon hd cards are usually better at video playback. both nvidia and amd cards will probably 'max out powerdvd 11'.
if it's a pre-built pc try to get at least a gtx 560 ti or a radeon hd 6950 if you want to play lates games at high settings.
also get a psu strong enough(80+ bronze or better) to power the gfx card(s).
I would suggest getting only 8Gb of ram (btw how did u get to 10?)
one configuration would be 2x 4gb + 2x 1gb on 4 slots.