how to set up two monitors with an ati card?

ok second post related to this. im trying to set up my view sonic monitor and my sharp aquos to sync up together. the only thing is i have the sharp connect to my machine via a ati pcie card and the monitor via the onboard video . if anybody heres knows please PLEASE tell me. i only have 1 day off work a week so this the only day i can do it.

By default any gfx card will disable the onboard output, unless there is some kind of hack for this you will have to buy a card with 2 outputs or a pci vga card.