If you aren't in the US it may be hard to find the GTS 450 on that budget. If so look at the GTS 250 and the HD4850, maybe the HD4770. If they are still too much then you'll have to go down a notch to the 9800GT or HD5670.
its already been answered... for ya, we spent 2 days answering alot of quetions seemed the best bet was a 5670 as you wanted dx11
for 100 bucks it seems liek the most powerful card you cna get but for some reason you decided ati was bad and keep commenting about how nvidia is better in other forums without adding to why beyons sayign things like "5770 not good because no dx11 or physx" when it is dx11 >_<
just letting ya knwo what you're getting into here jyjjy
Yeah, you are either going to need to spend more for a GTS 450 or go with an HD5670.
You can wait for Nvidia to release something between the GTS 450 and the GT 430 but you may be waiting a long while.
when they release the 550 which will be a few months if you can wait that liong i bet the 450's will get down to around a hundred bucks. if you were in the us, you could already find a 450 for a hundred after rebate