Hmm...
Currently, an I7 won't bring benefits into the gaming world, as hyper threading is not really supported as of now.
Therefore, if you want a new CPU, you should just go for an I5.
Apart from that, I've heard that the MSI 560GTX-Ti Hawk is quite good as a graphics card. It is only 200 euro's which is 1860 swedish kronor... The card itself has a good cooler on it and will stay cool.
Apart from that, I suggest you to get at least 4GB of RAM, which is now the standard. You will notice that your computer will work a bit faster, too. You can also choose 8GB RAM but for now it has no real benefits.
Apart from that, I think your CPU can still handle the job, therefore you only need to upgrade these two. I might be wrong though.
Oh and I am not sure how good your PSU is but you might need some more for the new video card.
I don't know which motherboard you have so I have no idea if these things are possible. It might be that your motherboard can only support to 2GB of ram and not more. So for that I suggest you check that out first. Would be kind of a waste if they don't fit.
