You need to review the specs on that video cards. Those ports were probably offered as in using only "one" in order to provide video due to port type connection, not offering dual video outputs. Thus, you need for simpler solution find a video card that actually support dual video output. If not, then a "magic black box" setup has to be found and this in turn isn't a cheap fix. The other fix is installing a 2nd video card, providing you have space and similar slots and cards for best operation. If not, then what's installed should work but no guarantee.
So, I have two monitors and a new Radeon 6670 card and both monitors are vga. I was wondering what I need to hook both up to the card to share a display. Problem is, I only have one vga port on the card and one dvi port. Can I just buy a dvi to vga converter and then plug both in like that? Sorry for the dumb question. Thanks!