Hooking up a 3rd monitor?

I have an Nvidea Geforce 7300 LE that has one vga port and one dvi-i port. I also have an integrated vga output, for a total of 3 possible monitor? I have SUCCESSIVELY connected and used 2 monitors, one is connected to the vga on the graphics card and the other one is connected to the integrated graphics card. Is it possible for me to connect a 3rd monitor to the DVI-I port on the graphics card? I have 3 identical Dell E196FP monitors. I have already tried connecting the monitor with a dvi-D to vga cable, but it didnt work (im assuming it has to be a dvi-i connector to vga cable)? if in my situation it is impossible, then what graphics card would you recommend?

Windows 7
64 bit
i have one traditional pci slot not being used.
and a pci express x16 slot currently being used by my graphics card.


(I have a total of THREE vga/dvi-i ports)
i have asked this question on many other forums and websites but no one seems to have a definitive answers that works. please help me, i really need to have a 3rd monitor. (im a day trader). Thank you very much