Always happy to help out someone from the motherland! o/
You'll need to tell me what kind of RAM you have though, im assuming PC2 something, as that model has a dual core processor.
but most of that model have at least 4gb from stock, so .... i wont take any chances.
you'll need to either open it up and check whats in there (it may be printed on the side of the SODIMM stick) or use a program like SIW or system information for windows, which will determine it for you. or google some other program that will tell you, your memory type.
it'll probably be pc2-6400 though, seems sony pumped that out in those models, but i can only go by what google tells me. And with sonys "build your own" system, the stuff inside could be completely different.
ebuyer.com do a good trade in the old RAM, dont go to the highstreet. PC world will rip you off