Widescreen LCD w/KM400 integreated graphics?

[chapd3it]

We recently purchased a few 19" widescreen Viewsonics that were on sale. One of them is hooked to an older PC that's sporting the KM400 chipset. I think it uses the S3 ProSavage DDR chipset. It looks like it should support the native 1440x900 resolution since it supports up to 1600x1200. Is there any way to get this PC to use the LCD's native resolution? I tried Powerstrip but that didn't seem to help too much. I also tried downloading new graphics drivers from VIA and they didn't seem to install properly. I also installed the latest driver for the monitor with no luck. If I need to get a new card, would something like a FX5500 or Radeon 9200 do the job? It would need to be AGP and fairly cheap.