I have £350 to spend on a gfx, was talking to a friend and he said that I might have to upgrade my psu as well as I have a 500 wattage one. If I can get one for £350 without getting a new psu that will be perfect but I don't mind getting a new psu (That won't change the £350 budget on my gfx). Thanks for your help 
EDIT: Would the 980 be the best one I could get for my money, I can probably afford that, but would I then have to get a new psu seeing as mine is only 500watts?

EDIT: Would the 980 be the best one I could get for my money, I can probably afford that, but would I then have to get a new psu seeing as mine is only 500watts?