might be a good idea to join nbr and post what you are after there http://forum.notebookreview.com/what-notebook-should-i-buy/
is £500 your max as you will only get a lower end lappy for that price which might struggle a bit on newer games.
£700-800 you can get a optimus technology with 555M switchable graphics upto almost £6000 for the beast of all beasts.