You are quite right. The GT210 is pretty pathetic. The GTS250 is about the same spec as a 8800GT. I'm not too familiar with the new line of mid range nVidia cards, but I think the 430 would suffice.
Is there a reason you are only looking at nVidia though? ATi has some really good mid range cards.
The HD4850 will give you similar performance to the 8800GT or even better you could get an HD5750 which could likely run the game at near full HD with decent performance.





