Can i change the graphic card on my laptop ??

I have recently bought a Samsung RF511.
It has Nvidia Geforce GT 540m 1gb
The graphic card isnt really great, but i can do some decent gaming on it.
I was just wondering if i could replcae it with a better graphic card in the future...


Full system specs (just in case..)

i7 2630Qm @2ghz (upto 3ghz with turbo boost)
6GB RAM
GT 540M 1GB also the built in intel graphics..
Windows 7 64bit