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. Computer Games on Laptop Graphic Cards
Even the top notebook cards - GTX 580M or HD 6990M - aren't going to reach the performance of a desktop GTX 560ti or HD 6870.