The latest GarageBand Version is GarageBand '11 (6.0.5). It requies MacOS X 10.6.8 or later.
Also, the lateset song I'm working on keeps going out of sync.
What is your GarageBand version? Are your problematic loops real instrument loops?
the only way I know to get loops out of sync would be to enable the "Tempo" automation for the "Master Track", change the tempo locally, but disable "Follow Tempo & Pitch" on the real instrument loops. That would cause your loops to stay at a different tempo from the main project. For example:
If you do not have a "Master Tempo" automation set, but still do see the same effect, your GarageBand Preferences file may be broken:
In that case I'd try HangTime's fixes for "oddball problems", i.e. delete GB's preferences and repairing permissions on your computer, as described in the FAQ, see: