1GB NVIDIA GeForce GT 525M vs. 2GB NVIDIA GeForce GT 540M

540M is better then 525M. 1Gb vs 2Gb is only relevant when the screen size is greater then 1600p
Cause 540M also costs more. 525M games averagely, 540M games slightly better, but neither can really do max quality. Laptop graphic still can't do what desktop do.

The rest of your post doesn't make much sense, more detail would help.

540M is notably faster but don't expect to max out all games with it

I am using a laptop.. 15".. i think 540m wont make a difference

It definitely makes a difference in gaming