Hey citizen! If your card is AGP (in the brown slot) then you're pretty much out of luck, new motherboards generally don't have AGP slots anymore.
Instead of replacing your motherboard you can upgrade your
ram, your board supports up to 3gb
ram (though it has four slots...I don't understand that logic...)
What you might do is get 4 512mb sticks for 2gb
ram, that should be plenty.
I can link some if you're interested