I say a 9800 GT should put you in high settings. But if i were you, i'd aim for something higher that's only a couple $$ more =P like a GTS 250. A little more power than you need, but just to be safe lol.
Now keep in mind these cards won't be supporting DX11 - but i'm assuming you don't want that (much less need it)?
* Windows® XP/Windows Vista®/Windows® 7 (Updated with the latest Service Packs) with DirectX® 9.0c
* 2.6 GHz Pentium® IV or equivalent AMD Athlon® processor
* 128 MB PCIe NVIDIA® GeForce® 6600 GT or ATI Radeon® 9800 PRO video card or better
* 12 GB available HD space
* 1 GB RAM (1.5 GB required for Windows Vista®/Windows® 7 users)
* DVD-ROM drive
* Broadband Internet connection
* 1024X720 minimum display resolution
PC Recommended Specifications:
* Windows Vista®/Windows® 7
* Dual Core 2.4Ghz Processor
* 2 GB RAM
* 512 MB NVIDIA® GeForce® 8800 GTX or ATI Radeon® HD 3870 or better
*Note: Due to potential programming changes, the Minimum System Requirements for this game may change over time.