Dual Monitors

I have an hp 6000pro desktop (windows 7). We are looking at running dual monitors. I have purchased an ATI Radeon HD 4650 Video Card
Thinking this supports dual vga, it has a dvi port and 2 display ports. the card also came with a dvi-vga converter and a display – dvi-d converter, and no one has a dvi-d to vga converter. Couple of questions 1st when i install the video card why isn’t the built in video card showing in device manager? 2nd since my 6000 pro also has a built in display port can i get by without another video card, if i get a display port to vga converter?