2gb Sapphire Radeon HD 4890 and 1GB in crossfire?

Intel Core 2 Duo CPU E8500 @3.16 (2CPUs), P5Q PRO Turbo,
Corsair 4GB 2x 2GB DDR2 TWIN2X4096-6400C5C, Sapphire Radeon HD 4890 vapor-x 1GB

going to upgrade RAM up to 8GB. Wish to upgrade a bit my old PC for just a few quid   Dont know much about it so any helping comments would be much appreciated.

Your cpu is a dual core it will bottleneck a lot of games.

Get atleast a quadcore cpu.

I believe If you crossfire the two, the one with the worse specs will be the one used.

So your 2gb ram will turn into 1gb ram.

It won't make much of a difference unless your doing mods

Cant afford to buy new motherboard and build up new system at mom, still if I will get that 2GB card and replace old 1GB plus get another 4GB RAM will it impove just a bit? or what CPU U will adivise to buy to these to make it run better? Thanks for your time anyway