Buying any computer for gaming is going to be a rip off unless you get to specify each part for them to put in.
There are a few companies that will do this for you (ibuypower, alienware) but they charge so much you're still getting ripped off (like, 5 grand).
Unfortunately when it comes to laptops and gaming there aren't any perfect solutions. They are meant to be just that, a lap top, not a gaming computer.
Same downside with buying your own desktop, like what Patonb mentioned earlier with integration. 95% of companies use integrated GPU's, which in a nutshell means 'Can't run games well'.
Putting that 6770 in will probably do the trick, but if you want to do some serious gaming I'd look into a desktop or an actual gaming laptop