You can not put a desktop video card into a laptop. The form factor is complete different and will not even fit into a case. It would be like replacing you laptop's keyboard with a Logitech G15. It just won't fit.
You also most likely will not be able to fit a Go series card in either. In VERY rare cases, you maybe able to upgrade a current discreet video card if your laptop already has one. However, laptop are designed to handle only a certain amount of heat output and provide only a certain amount of power. In fact, you probably won't find an interface to plug in a video card on your laptop's motherboard. Even if you do, there won't be space for the discreet card or you won't be able to find a GeForce Go card cheaply. The Go series is NOT sold for retail. Laptops are for the most part NOT upgradable and are NOT for high-end gaming.