You are going to be one happy camper when you finally do. That said releases are approx for Q1 2012(big emphasis on approx). If you are willing and can wait then of course it would be best to wait and see what the new 28nm tech is capable of doing. If you really need it then there is still nothing wrong with the available cards today it will last you a long time.
All of the AMD 5xxx and 6xxx cards, as well as Nvidia's GT/GTX4xx and 5xx cards. One of them should interest you.
If you already have a 9800GT, you should be looking at a GTS450, GTS550, or 5750/5770 (6750/6770 are the same cards with a different name.) minimum. GT430 and 5670, etc are all slower then your card. Not sure what prices are across the pond.
All cards of the last two generations by both Nvidia and AMD are DX11. For your current CPU the 9800GT is already overpowered so don't bother until you upgrade.