well 500 euro will put you somewhere in 750USD range.
In that range the options are as follows:
llano laptop - preferably A8 if it fits your budget, it should play SC2 with no problem and give you great battery life
next runner up if you think llano GPU will not be enough is i5 with a GT540M or equivalent range on ati gpu
if you pick anything better it'll be out of your price range