My first post here so be easy on me

OK i havent played pc games in years. My last time being flight sims like falcon4 and janes f/a18 etc. But when i saw a subsim i had to give it a try. My problem is low framerates and sometimes a crash and i hate using low settings for anything let alone a sim with the detail SH5 has. I run windows 7 64bit with a intel quad core 2.4, 2 gigs ram with a evga gt8800 that runs no hotter then 49 degrees F. I also have the asus
XONARHDAV1.3 hdmi audio card because this pc is my main htpc for blurays. Anyway all drivers are up to date now which helped alot. My question is i have a friend willing to sell me a
evga GeForce GTS 250 superclocked and was wondering if that would help my case at all or should i go with something newer?
Thanks