8GB RAM is now a very good idea.
Most games can do all right w/ full 4GB RAM (closing anything else).
But with some new games like the new Batman you will really see improved performance w/ 8GB RAM.
your gpu is not bad:
"The gaming performance of the GT 525M is similar to the GT 425M as the core clock rate differs only by 7%. Therefore, the gaming performance of the GT 525M is sufficient for medium detail settings in modern games like Battlefield Bad Company 2. Less demanding games should run in high detail settings. The best resolution to choose is 720p or lower due to the limited performance. Benchmarks and comparison charts on the 3D performance can be found below or on The dedicated GT 425M benchmarks page is a great source as well due to the similarity between both GPUs."
Ref:
http://www.notebookcheck.net/NVIDIA-GeForce-GT-525M.43889.0.html
Your cpu is capable of 4 threading processing (HT) so will do ok w/ most of games.
However I think some BF4 multiplayers maps can become a challenge for this little Sandy Bridge.