If the card defaults to the IGP you would have to try and do it blind. Try and look at the menus in the user manual and figure out exactly what key sequence you need to get to the right menu to change it after booting into the bios. You can try as many times as it takes, just reset the bios after each try.
THANKS. It would be nice if someone else who has a am1640 e1510b could post a of the bios screen.