Is it possible to enable onboard video card with PCI-E card?

I recently bought a Dell Dimension E521 desktop. It came with NVIDIA GeForce 6150 LE Integrated Graphics card. I installed NVidia 7600GS card with dual DVI out yesterday. I have 3 monitors, 2 connected to the DVI ports on the 7600GS card and was wondering if there is a way, I could use the 3rd one on the integrated one? I wasn?t able to get the integrated one enabled after installing the PCI-E card.

Anyone have any solutions? OR I have to get another PCI video card?

Also, will DVI splitter help? I know with the splitter I can connect two monitors to one dvi output, but will this allow me extending my desktop? I don?t want to get the same screen on two monitors.

Thanks.