This is the connector y'all are on about
http://en.wikipedia.org/wiki/DMS-59 It's not DVI and it's not VGA, though it does look similar. You can't use a dedicated GFX card + integrated GFX unless you've got "hybrid crossfire" enabled motherboard & GFX card - which you almost certainly won't have. Make sure you do have a PCI-e x8/x16 sized slot and not just a PCI or AGP.
That nVidia card is ancient but specifically designed to be used in workstations. The ATI card on the other hand is relatively new but is designed for home use. Given your budget you really can't be needed the specialist benefits the nVidia card is offering, so for that reason I'd go for the much newer (will be more energy efficient, probably produce a better picture, will be faster to render, still has driver support etc etc)
Q for others - do you need a DMS port to output two independant displays (i.e. extended desktop space) from a single. Or is DVI/VGA capable of doing that, as I believe Displayport is? Presumably, in a similar way to interlaced pictures, DMS shoves the data to the splitter in turn and the splitter has a filter, or the screen itself can interpret whether it's supposed to be screen one or two.