I had a similar problem, you see graphics cards priced at £100-200 and wonder if you can get a decent one at a reasonable price.
I opted for a winfast A180B card at £40, it has 128Mb DDR and so far I am very happy with it.
But I think you will need more than one opinion befor you make your mind up!
Hope this is of some help
(btw it should help speed up you machine to some degree, depends what you are running?)