Depends on your laptop. After nVidia introduced the MXM standard which is a PCI-X standard for notebooks, replace (by you) graphics in your laptop will be an option.. ATI has something on the way as well which probably won't be interchangeable with the nVidia standard even though the specs are not owned by nVidia and can be used by whoever decides to built a graphics card for laptops...
Guess the answer is no - not even by a professional...