Who is going to upgrade pc for IL-2 CoD?

[camel24hrs]

Hey guys I am new here. I have visited this forum over the last two years waiting for info on the release of SOW. I have preordered the COD. And now I am thinking of upgrading my graphics card. At present my system is:
Asus P5K deluxe
Q9550 overclocked @ 3700
4 gig of kingston hyperx 5-5-5-15 @ 1066
MSI Geforce 9800GT 512meg OC
Vista 32 OS

I am not in the place where I can just go out and do a total rebuild, so I am looking into doing a graphics upgrade that will enable me to run COD with all the bells and whistles. At the same time because of finaces I am not looking to exceed that performance, in another words what can I get by with.

I am looking at two graphics cards right now.
Evga geforce gtx 560 SC
Evga geforce gtx 570 SC

Been a long time since I have shopped for cards and I am looking for input as to if either one of these cards will run COD on my present system with all the bells and whistles turned on and also what kind of differernce is noticeable between these two? Thanks in advance for any help.