Hey Claude,
You have a laptop right? Getting a video card for a laptop is going to be tougher because its hard to say without seeing what bays you have available in your specific model. You'd probably want to do some searching on what others have put into your model.
Another thing you can try is updating your video card drivers, etc.
Otherwise, for gaming a desktop is usually the better option because you can upgrade / modify to your heart's content.
Feel free to post your model / specs and maybe someone can help you further.
