That's a tricky price point for decent gaming performance. I'd say check out the Lenovo Y510p or Y410p...a GT 750M is about as good as it's going to get unless you pay more, or get a smaller screen:
http
/shop.lenovo.com/us/en/laptops/ideapad/y-series/y510p/ - $800 - 15.6" 1080p screen - GT 750M
http
/shop.lenovo.com/us/en/laptops/ideapad/y-series/y410p/ - $800 - 14" 1600x900 screen - GT 755M
Still you're looking at more like 30-50fps on medium settings. Slighly better with the GT 755M
Cheers