One you have to have atleast a 4x AGP slor to use an AGP video card.
Two your motherboard probabably doesnt support a processor that is much faster. But I will see what I can find.
I am guessing this will work. It is only lke $60 bucks. From what I could find the Duron you have has a 200mhz fsb and so does this chip.
The XP has a silghtly higher fsb and could work in your system properly if you fsb supports those speeds, but until you find out more you will never know.