My 1st build, GPU advice

Hey guys, 1st post on this site, seen a lot of good advice on here so could do with a little help on GPU choice!

I have compleated my 1st home build, im used to building servers for work so this was fun to bulid something at home to have fun with, primarily going to use for gaming, hopefully 1080 on a 40'' samsung TV

I have already performed some overclocking and the system is currently stable running

Asus M4A88TD-M EVO/USB3 AMD 880G (Socket AM3) uATX DDR3 Motherboard
AMD Phenom II X2 560 Black edition duel core 3.3Mhz, currently Identified as Phenom II X4 955 Black edition Quad core OC'd to 3.7Ghz
4GB Corsair DDR3 13333Mhz Memory
Lian Li V1000 Aluminum PC Case
Jeantech 700W PSU
Samsung Blu-ray disk drive

Im on a budget so in my price range was thinking Sapphire 5770 £95 from Pixmania, prob Xfire 2 at a later date
(http://www.pixmania.co.uk/uk/uk/4122063/art/sapphire-te...)

If anyone could advise on something better it would be appreciated, i know a lot of people will say get a more expensive card rather than 2x 5770 but i wont be thinking of getting another for a few months yet, and id love a nice card to get it running now, play ST: online and will be playing the old republic when it comes out.

Cheers guys