An Alienware Graphics Amplifier will be launched exclusively for Alienware 13 Gaming laptop only.
"http
/www.pcworld.com/article/2839436/the-alienware-graphics-amplifier-lets-you-add-a-desktop-video-card-to-a-laptop.html"
But what Mr stickmansam has said stand correct. I will quoto him ,"it's not worth it while it it technically possible".
Also Laptop tends to heat and overheating can possible damage your parts and in absence or low working of cooling fan can make your laptop shut down unexpectedly!
It is better that you buy a new Desktop for Gaming Purpose only !