With that price range, build a tower. Seriously. You will never get a laptop to play games worth a damn at that price. I actually have the DV7-6B75NR that has a i7-2670QM 8GB RAM and a RADEON 6770M 2GB DDR5 and it can actually play every game I’ve thrown at it @1080 on high (but not ultra), but this machine is about $1,300. I had the one you referenced first and it is a TOTAL POS, don’t buy it. I'm sorry but it is a LOT slower than this one.
I say you take that $600 and build a tower, which also will be upgradeable.
Also the DV7's run hotter than the sun.. Mine runs at 95C while on a cooler on a table when playing games. The max is 102C. The turbo boost runs at 2.5GHz at that temp instead of the 3.1GHz max.
And i've also had a fair amount of issues with mine (BSOD's often, Wouldn't boot in to windows, had to restore, happened twice) I wouldn't recommend them. They're impressive and powerful but they put too much power in these laptops without addressing cooling i think that is the root of the problems.