Yes your computer will accept a discrete graphics card. What do you use your computer for and how much is your budget? You will have to upgrade your power supply to power the graphics card though as you only have a 220watt. You will need a 300watt or over depending on the graphics card.
Are you sure it's just a graphics problem? Is the rest of the system powering up okay?
It would seem a shame to put a graphics card in it and it didn't work still