Let's start with the fact that the GT 540m does not meet minimum requirements of the game.
Do not be misleading large amount of video memory, even an old 8800 GT to show the best results, as it is at least twice the performance, despite the smaller amount of video memory.
GT 540m - designed for simple games, browsing the Web and watching videos, it's not a gaming video card and you should not rely on the 30-60 frames per second even at minimum settings.
