Went to Apple store this morning in Palo Alto to ask about my time problem. Turns out, I didn't need a new battery. I just needed to reset my power management system—which also explains the trouble my machine has started having waking up from sleep. This is done (on the Powerbook G4 12") by hitting ctrl+alt+shift+power (when unit is off). I'm not sure why I didn't think of that. Seemed to do the trick.