You are going to have issues since thats a laptop your trying to upgrade. I dont think you will be able to upgrade it. I do have a Alienware M17xR4 with a 675m. It plays pretty much everything on high at 50+ fps.
You can't upgrade the graphics card on most HP laptops because the Graphics card is either soldered into the board or custom designed to fit your laptop. Even if HP could do it for you they would charge you an exhorbitant amount of money. You might as well build your own Desktop or get a new gaming laptop.
Tom's actually just did an article on this not too long ago...