Umm, it's a Morgan core... crap... not all of those even make it to 133/266fsb, I forgot about that... I'd have to advise that you ditch that off to someone for $25 and find a tbredB 1700 at least for $30 or so...
Umm, and after looking at things, your ATI chipset mobo... umm, maybe bundle that with your Duron and ditch it as well? There's absolutely no sense in upgrading it... it'd be like putting an XP3200+ into a KT133 mobo. I'd say $20-$25.
Then go to newegg and go to the refurb section and throw down for at least a KT333 mobo. So if you had a 1700 and an overclockable KT333, THEN you'd be primed for serious improvements. You might be able to get 166-200 fsb, 1.9-2.4ghz out of it, and then your ti4200 woul dlove you even more... and heck, at those speeds, even a 6800 series card wouldn't complain too much.