even if is just on 32 bits, it can use up to 4 GB in a 64 bits operating system. And I'm sure if it is not on 64, it will get there, sooner rather than later.
yet, for a laptop with a rather week video card, getting 8 GB of RAM it is overkill, considering the low resolutions in which you can play.
I'd rather save it for a good desktop in your place.
The best thing you can get to upgrade your laptop in order to have IL2 CoD benefit from it, would be a SSD disk. A better processor would be better, but I don't know how much would a really good one, which also fit your motherboard, would be. and maybe a (external) video card..
what about a new laptop
?!