You cannot use the ATI Video card & Integrated Video Card on the motherboard of the computer at the same time. The integrated video card becomes disabled once the ATI Video card is in place. If you want to use dual monitors you need a video card that supports dual output from ONE video card.
I don't know if the ATI 1300 supports dual displays. If it does then you can setup a dual monitor using the ATI 1300 video card.