no, it sounds like a 1.9 ghz, which is between a 2800 and a 3000, so it would either be just as good, or slightly better
and yes, AMD is better for gaming
large difference? not really. you'd be buying a new cpu and mobo anyhow. just wait some more, and then upgrade/buy new pc. not worth it yet; your amd 1.9 should be fine for a while longer. ive got an amd 1.4 and ad p4 2.6. not that different at all. things load a bit faster, startup is little bit faster, but nothing significant.
or just dish out 300 bucks and get a Asus K8V SE and a Athlon 64 2800-3200+ (which ever one fancies you)
Wait for PCI-Express, DDR2 and all the fancy new technologies to be incorperated into AMD design (currently known as BSX [Intel currently has them]).
A PCI-Express gfx card would be VERY fast (I believe around 16x, but just runs hella faster than AGP?). Wait for that, and wait for the prices of DDR2 to fall.