Wow...you're quick to select a best answer.
Anyways, take a look at Tom's Graphics Card Hierarchy Chart for a good reference:http://www.tomshardware.com/reviews/best-graphics-card-game-performance-radeon-hd-6670,2935-7.html
A 9500GT is not very good at all, so anything new for more than $40 will be a huge upgrade. From a performance standpoint, a GTX 260 should give you about 5 times the framerates of a 9500GT on the same settings.
A Radeon 5830 was for sale for $100 not too long ago. I'd try to get one of those for that price. Otherwise, go for a Radeon 5770 or GeForce GTX 460 768MB. Keep an eye on Newegg deals (get on their email list) and slickdeals.net to find a great deal.
Are you planning on buying right now or are you willing to wait a couple days or a week for a deal?