16GB RAM won't add too much performance, since games rarely take up more than 5GB RAM. As along as you don't have too much bloatware or are not multitasking extremely, adding 16GB ram won't add a perceptible performance increase.
On the graphics side, no. You can't upgrade the GTX 960M as it's soldered on to the board. Only those hulking, thick, full-size gaming laptops have MXM cards (mobile PCI-Express cards that are replacable) and even for those, upgrading is expensive.
Regarding low FPS, on what games are you experiencing difficulties? GTX 960M is fast, but not exactly the fastest card. You can't expect to max out everything on everything. Without knowing specifics I can't help much.