That's what I was suggesting, I mean the processor is a lot more pricey to upgrade, and pbviously harder to install than some new RAM.
BF2 will run well, just possibly not at the top of the ladder in performance. Now everyone thinks that this is a bad thing, but you've got to remember, only buy what you can afford. I made the mistake of originally setting out a £1200 budget, and ended up spending £1500+ for my new system.
Adding RAM later will greatly improve your performance, and will cost less and give you less hassle than upgrading the CPU