^^ Ditto. Unless you bought your laptop from a dedicated gaming laptop builder which used components (particularly the MB) which are easily up-gradable, trying to upgrade a laptop is a very, very difficult proposition. Selling and rebuying a new one is about the only real option. For 1000-ish USD you can get a 17" 960M gaming laptop which will run AH3 and other games "ok", and for 1300ish you can get a 970M of the same, and be right in there for a lot of games including AH3.
Gaming laptops will shortly be getting a big boost from better CPU tech for them, and MUCH better GPU tech - you can now get non "M" and full GTX nVidia GPU versions of cards in some laptop builders, and more/better stuff is coming. Full 980 GTX laptops tested against similar desktops are nearly identical in performance. They always cost more though.