GTX 560Ti ; reason; when newer titles come out, you'll be able to enable the use of physx(if the game played supports it) on par its as good as the 6950 but teh only upper hand any of these cards have is the the GTX 560Ti has Physx...thas a selling point for me. Otherwise, they are the same.
look at this chart
and post back with where you find your GTX be located...:)
Your a good candidate for a GPU upgrade as the GPU to be bought is actually 3 tiers higher than the one you own.
Everything else checks out fine
Your all set to put it in your cart.
Edit; you sure you need 2GB? the extra GB is for monitors having res's over 1080p/monitors running over 23"