No chance mate!
Without even going into the nightmare of physical challenges of even fitting a new card to a motherboard that hasn't even got the space, or slot for it, you'd have to be able to re-write the BIOS to recognise it, manage its power supply, AND ignore the existing chipset!
Out of the question.
Put this one down to experience and remember that laptops are primarily for mobile general computing, and for gaming they represent the absolute luxury/premium end of PC hardware when compared to the cost of equally powerful desktops.
If you want to play this life-sapping game you have no choice but to get another system capable of playing it, or upgrade a desktop PC you may have access to instead.
For a few hundred $ you could have a brand new desktop that'd play almost anything you throw at it.
To be honest, a laptop's gaming performance is not upgradable in any practical/economical sense.
If you spend a couple of thousand pounds on an absolutely top-end gaming laptop, you'll get a few years life out of it before it begins to show its age, and then a couple of years more with lower quality settings in your games, so not that bad an investment, but the initial outlay is huge compared to an equally as powerful desktop, and you have no choice but to pay all over again once you do need to upgrade, instead of just replacing the parts that need upgrading.
Besides, at those levels of performance, the only advantage a laptop offers is being able to move it from one location to another more easily; you'll still always have to plug it in because proper gaming takes a lot of power that batteries can't offer for any reasonable length of time.
So you'll end up plugged in to a wall anyway!
Finally, the cost of mobile chipsets can be as high as double that of their desktop equivalents. Basically close to the cost of a cheap desktop!
Basically, assuming you have no other options as far as access to an upgradable desktop is concerned, a new entry level gaming desktop, without a monitor, keyboard and mouse would set you back at least $400-500.
an i7 really isn't needed for high quality gaming. Most games right now dont support 12 virtual cores so a lot of it goes to waste. I got an AMD Athlon X4 2.9Ghz and it works great along with my new Radeon HD 6850. No need to spend so much on an intel processor if you don't need it. Put the money elsewhere like a good graphics card and reputable parts.
Each to their own 