A dual core i3 2100 will outgame the 1100t for less money, and a 2500(k) or 2600(k) will game even better. Why? Simplistically, these Intel cores clock faster and do more work per clock than the AMD cores, and games are not multi-threaded enough to make use of the 100t's advantage, more physical cores.
You might save a bit more money choosing a lower power but still high-quality psu. Since the entire system is unlikely to require 450W from the wall (<405W from the psu) even when running Furmark (446W):
OTOH, the 650W may be a bit underpowered to handle 2x570 should you care to protect against future SLI, and you should probablt consider 750W-850W eg in that case. You don't mention your screen resolution, but if you are running 1920 you don't need SLI on the current set of games.
Dont bother with the suggestion to use an intel cpu . For high resolution gaming a stronger cpu does nothing . The limitation is always the graphics card .
And an i3 2100 can sometimes out game a phenom x4 , or x6 but in the real world for system builders this never turns out to be true
So save yourself the money and go with AMD
But there are some changes to make .
The X4 955 phenom is the best value , and as mentioned previously it can provide all the GAMING performance of the x6 because games are not that highly threaded
And in just a few days , maybe even tomorrow , there will be new AMD Bulldozer processors released
That brings me to the second point .
Your motherboard sucks . Its a model made with a very old nVidia chipset . They were not good back then , and theyre definitely not good now .
For best performance now , and compatibility with future AMD processors you NEED a motherboard with an AMD 990X or FX chipset
These can crossfire and SLI