What was interesting was that when I first put the card in there and powered on, it defaulted to the new card.
Windows was able to use the card, albeit at low resolution, but the monitor complained about the refresh rate (I think) when I tried to turn the resolution up to 1280x1024, the max available in the Screen Resolution dialog.
Naturally, the display defaulted to 640x480.
So, windows could use it, anyway. There aren't some generic drivers that can be used just to get the extra VGA port?
Current nVidia drivers are compatible with all GeForce 6 and newer GPUs. You can get new PCI 6200 and 8400 cards starting at around $50. The 6200 in particular is quite common in the bottom of the market.
If you have a PCIe x16 slot, there are plenty of Win7-compatible cards for less than $30.
AMD does not support officially Windows 7 on any GPU prior to the HD2000 series nor does nVidia for anything earlier than the GF6000 series.