Very very limited, usually only SSD's as laptops have soldered parts. To OP, as others have said, building is the best way to go. You can build a decent rig for 500-650 bucks that'll out perform any prebuilt store PC. If you are willing to do that, that's the best way. If you are really on a budget, depending on your specs, you can pick up a GTX750Ti or R9 270X that'll run GTA V decently but as mentioned before, depends on the other specs you have.
Alienware is way overpriced. Literally the Apple version of PC gaming xD