I don't think GTA V is out yet? Have you seen any official system requirements anywhere?
I'm not familiar with that last game.
But it's system requirements are quite a bit less than BF3.
A $2000 budget is enough to get you a notebook with chance of running BF3 on high settings. You might need to tweak the settings some, and maybe lower resolution. The GTX 560M graphics cards in the ASUS G74SX / MSI GT780R might not get the type of game experience you want. If you compare the GTX 560M to desktop cards you'd be looking at about GTS 450 level performance.