Computer Help Please?

[Krimbo]

Ok I know this is so off-topic but I feel like this forum will be a beneficial help in the advice I seek. Please don't take this the wrong way. I just don't want to throw away money on things I don't need.

I'm looking at upgrading my desktop computer.
It's pretty average and I feel like I should be getting spanky-new parts ready for all the huge games coming out in November.
However, I'm pretty stupid with everything under-the-hood.

So here is my current set-out;

Intel Core i5 Quad 720 @ 2.67ghz
Nvidia GeForce GT 220
Memory 2gb

So I know I definatly need an upgrade in RAM.

I have no idea about processors. Is that good enough to run the new games of 2011 and 2012? I'm going to be upset if I can't play Skyrim.
Is it worth getting an upgrade?

The graphics card is a really common card in standard machines.
I'm looking at the Radeon 6970 and the 5870.
Does anybody have any recommendations?

I've been looking at the AMD Fenom 3.2 Quad Processor.
Some websites say a new processor needs a new motherboard but others said you didn't.
I've also been looking at the i7 3.4 Quad Processor.

I'm really stuck here guys.
I know this thread really shouldn't be here but I hope my fellow Frictional fans can help me!