I don't think it is possible to attach a GPU to a laptop. Laptops lack the proper slots or space for graphics cards, so it looks like your friend is out of luck for the moment.
Upgrading the GPU on a laptop usually means replacing the entire CPU, due to the use of integrated graphics chips in most laptops.
Also, not only is replacing the CPU a massive pain, but it can often mean voiding your warrantly as a result.
Sometimes, even better CPUs don't necessarily have better GPUs either. You could end up seeing the same graphic capabilities in an i3 as an i7.