Don't forget u changed ur drivers which also could have had some effect. If not then you will just have to face the fact that it doesn't work anymore.
You can pick up an MSI R4350 which is $40 and can run shaders on Max with literally maybe 20 bricks or less and then on low with a bunch of bricks .
For other games you can run 64x64 texture packs in minecraft and still have playable frames, around 30-40. Not bad for a $40 card.
If you want to you can spend an extra $20 and go for an AMD 6770.