Best Graphics Card For £300

APPROXIMATE PURCHASE DATE: 2 week
 BUDGET RANGE: £300
USAGE FROM MOST TO LEAST IMPORTANT: Gaming on games lije battlefield to gta
CURRENT GPU AND POWER SUPPLY: no current gpu. getting a corsair 800w psu.
 OTHER RELEVANT INFORMATION: mobo is asus p8z77-v lx. i7 with ivy bridge. 16gb corsair ram. HAF 922 Case.
 PREFERRED WEBSITE(S) FOR PARTS: preferrably a uk website but will buy from abroad if its cheaper
COUNTRY OF ORIGIN: England, United Kingdom
 PARTS PREFERENCES: No Preference
 OVERCLOCKING:  Maybe 
SLI OR CROSSFIRE: seriously consider this
MONITOR RESOLUTION: 1980x1200
 ADDITIONAL COMMENTS: should be able to handly GTA 1V And BF3 comfortably as well asa few driving sims