I strongly suggest just finding a good, cheap desktop as they are more powerful and reliable while still in your price range, but if you do need a laptop to move around with then I would suggest http://www.amazon.com/Acer-Aspire-V3-572G-54S6-Gaming-Laptop/dp/B00MM2WA8O/ Take a look, I've suggested this before to friends and they seemed pleased. Good luck!
Edit: Asus also carries higher end gaming laptops, but most may exceed your budget. It may be worth checking them out too though.