More RAM for better Graphics performance

I have been running a games, Empire Total War, and it has become laggy. I was wondering if upgrading my RAM would help the performance. My system is as follows:

21.5-inch, Late 2009

Processor 3.06 GHz Intel Core 2 Duo

Memory 4 GB 1067 MHz DDR3

Graphics NVIDIA GeForce 9400 256 MB

Software OS X 10.8.2 (12C60)

This is from Activity Monitor 30 min after running game:

Free: 858.5 MB

Wired: 742.9 MB

Active: 945.8 MB

Inactive: 1.51 GB

Used: 3.16 GB

Vm Size: 243.90 GB

Page Ins: 838.8 MB

Page Outs: 394.3 MB

Swap Used: 432.8 MB

Would increasing my RAM increase the performance or should I be buying a newer computer with a better graphics card?