What should I upgrade my gaming PC with?

I'm trying to get TOR to a reasonable FPS even in graphic intensive scenes and cities. i've managed to wrangle a standard 30-40 fps which is absolutely tolerable, but it drops down to 20 or so in congested areas, and plummets to 5-7 fps at times, which is very uncomfortable. This is at the game's Low setting. I'm not a tech savant, which is why i'm asking here for a second opinion - but I am comfortable with overclocking.



Here's my specs:



Windows 7

Asus motherboard. Not a very good one - does not support CPU bios overclocking.

Intel Core 2 Duo E8400 CPU, 3.00 ghz (Potentially overclockable, but my motherboard is locked down tighter than fort knox)

GeForce 550 Ti overclocked by roughly 25% using EVGA Precision.

3GB Ram

Sufficient memory %26amp; power supply.

Fan cooled case, but considerably well-to-do for what it is.



Trying to identify the pieces that are most desperately in need of replacement. As I said, i'm using this rig for gaming, and i'd like to get it in respectable shape. I'd like to do this without breaking the bank as much as I can.



Currently my thoughts are to upgrade the RAM by a GB or so. Windows 7 is a memory hungry sucker, and I notice in task manager that my hardware memory is often capped out when i'm playing TOR. But then i'm divided because it is, naturally, a FPS issue. Upgrading my GPU would be a little more expensive, but i'm not sure if upgrading the CPU would be a more framerate-happy way of helping my PC. I had heard of people using two graphics cards at the same time - I could consider buying another geforce 550 TI to pop in there, but would that be better than buying an entirely new graphics card?What should I upgrade my gaming PC with?
I'd say get at least 8 GB of RAM and get a really nice graphics card and maybe upgrade the mother board.What should I upgrade my gaming PC with?
I would upgrade the motherboard. Do a substantial upgrade, don't go out and get another board just to support your current processor. Get a new current board that supports a core i5 - core i7 and get yourself a new processor while you are at it, BUT you will need new triple channel memory when doing it, almost all new boards will require DDR3 with the exception of some odd ends. Might as well get 8gb of memory, the more the merrier.