apple speakers

I'm CURSED!

ok. so first I bought some crappy speakers, and they work with my G4 running OS X. however, they sound like crap. to be expected. so I take them back to Fry's.

So I think "This time I'm going to get good speakers!" so I get the purdy clear spherical apple pro speakers.

for some reason they do NOT fit the jack in the back of my computer. wth? the jack on the back of my computer is larger than the cord plug thing...

is there some kind of adapter I can get??? or do I have to take these back also?

if I have to take them back, what SHOULD I get? :( I want two things:

(a) really good sound
(b) works with my G4 500 mhz running OS X
(c) doesn't cost an arm and a leg

*cries* I wanted the purdy ones to work!