Hi Wally,
Sadly I have to say that with the Graphics Card you have bought you won't be able to do what you want.
You really need to take it back and exchange it for a card that has either 2 DVI outputs or 1 DVI and 1 AGP port. This will allow you to disable the On-board graphics chip and you can run 2 monitors from the one Graphics Card. If you look at the image in the link I provided previously, you can see the 2 monitor connectors.
If you want to use the Graphics card along with the On-Board Graphics chip then you will need to exchange the 5 Series card that you now have for one of the 4 series cards.