You think thats expensive for a graphics card? Last one I got was around $370 and its not even top of the line.
If you want to use Aero then you need a fairly hefty graphics card.
What you were sold must have been really bottom end if it was new less than a year ago and only has 32Mb RAM and doesnt support DX9.
I guess you dont play games.
Video editting is very different than 3D rendering, video playback really doesnt ask much of your graphics card.
Vista's new Aero interface allows you to move windows around in a 3d virtual environment - cos that was really missing from my life - the ability to lose track of open windows in 3 dimensions instead of 2

I wouldnt touch vista with a barge pole personally - I have a powerful gaming machine - but that doesnt mean I want all that juice diverted to my OS. If I wanted unecessary whooshes and spongles and prettyness, I'd get a mac. What were they thinking?!
But I digress. Which card to get depends whether you're AGP or PCI-E, given that your computer is quite new PCI-E is a possibility, however given the specs of your current card, its probably AGP or onboard.
First thing you need to find out is what motherboard you have. Then you will know where to start looking.
You can pick up a 128Mb AGP 4x/8x with DX9 support for around $30 but exactly how good that would be... I dunno - I'm more of a $300 bare minimum kind of gal