can i put an ati radeon 5800 gpu into an hp pavilion g7 laptop with an intel i3 processor?

I recently bought Battlefield 3 for the pc, and i was surprised to learn that the hp tent g7 notebook i bought didnt come with a graphics card. it was a budget laptop at the time, and now i want to turn it into a gaming rig. i know i can update the ram, but can i update the graphics card, also, what kind of graphics card is compatible with associate i3 processor. any help would be greatly appreciated.