oh gee, just converted dollars to pounds that's bascically a budget of 355... my normal computer is worth more then that and it's not even a gaming pc xd. I'd recommend as Godz said saving more money, as you're not going to get too much better of a pc then you probably already have. Even if you was to buy the parts individually there's only so much you could buy in your price range. I personally am going to be spending around 1200-1600 on my next new pc at the minimum
. (which in dollars is 2000-2700)
Just look up different types of gaming pc's and then look at the specs of each, and then research and look into every part so you know what your getting for what price and what quality.