If money is no problem, then patience is a vitrue!
There is nothing to buy today to make this game run very well.
Wait for the next generation of NV GPUs with the new core. These will make the game run better.
Now the bad news, they decided to postpone the introduction of the new GPUs from end-2011 to 2012
So, very sad Xmas it will be!
GTX580 3Gb is a good card to get you fixed for a few months while waiting.
~S~