If you want to do it the easy way, buy an entire SOHC Neon tranny, take off the clutch housing, and replace it with your 2GNT clutch housing. That's the real basic way of explaining it, however, as you'd still need someone to set your diff preload.. it'd probably be better to have someone else do the actual trans work.

As far as just swapping the gears, i don't know.. Murix? Armond?