The 540m seems okay, with that budget u could def get better.
it also looks like that this card does share some of your system memory which can slow u down in some games
This is a pretty well built computer. It has a GTX series mobile GPU which is a lot stronger than a GT series, it may require a little more juice, but thats what power adapters are for.
Also with the above system.. Add a 500GB 7200rpm drive, 8GB memory and a killer wifi card. price is 1337$ obviously u must get it