Laptop Graphics Cards - Help

[FormidableRed]

Hello,

So, I bought myself a laptop from pcspecialist, and I got it with a: NVIDIA® GeForce® GT 645M - 1GB DDR3 Video RAM - DirectX® 11

It was either that, or the standard Intel graphics card on the drop-down list - Does that mean my laptop will only support the GT 645M? Or can I upgrade to a better one in the future?

If I can, where is the best place to buy new graphics cards from? (I'd prefer a 2GB one)

 

[Toxophilix]

Unfortunately, PCS have posted here in the past that it's only the Skyfire and Vortex models that allow this. The other laptops have the GPU soldered to the motherboard.