from your description, I assume your card has two DVI connectors.
Please check the documentation (or ask the manufacturer of the card), which kind of DVI interfaces are used. To connect your VGA monitor, you need DVI-I (or DVI-A) connections. Any inexpensive DVI-I to VGA adapter should be fine then.
Maybe this is helpful also: http://en.wikipedia.org/wiki/Digital_Visual_Interface
I’m pretty sure it’s this
Of course I already have one of these for my current monitor but can’t get at it while the computer is on. I’ll unhook it tomorrow and see if I can find a match for it locally. Silver lining getting hold of that ATi 4000 series card, had no idea it had twin ‘outs’