Yep, get a graphics card. You did not list any computer or video adapter brands, models, what application is playing poorly, monitor resolution, really any detail that will help figure things out. Without the right info, any suggestions are just guesses.
Best bet, lower the resolution and see if that helps, don't expect movies or games to run well on that setup.
can you comment on which of these cards would be best suited for my windows 7 system? -
ASUS EN8400GS SILENT/P/512M/EU GF 8400 GS DVI ( HDCP )
Radeon HD 4350 DVI, HDMI ( HDCP ) - HDTV out - lite retail
The video card you pick will have to be based on what kind of case you have, how much power your power supply makes, and your uses for the computer. Need that info for a good pick. Either of the cards you listed will run in pretty much any system, but why not just use the adapter for the DVI port on the motherboard? If you have space to plug in a cord, you have space for the adapter.
If those cards don't have VGA ports (which they may not), you'd need an adapter anyway.
Matrox, although not good for gaming, is a strong company for multi-monitor display, this pdf will help you choose, there is a listing of how many monitors they will support. Keep in mind that the cards are hundreds of dollars for quad displays, but you may be able to find a used one. http://www.matrox.com/graphics/media/pdf/products/en_pr...