Purchase a UPS (uninterrupted power supply aka:backup battery) they are good for a number of reasons. 1 they protect against brownouts (voltage drops-as damaging as surges)... but surge protectors do not address this problem. 2 They also isolate phone/data lines from lightening strikes. You don't need a large expensive unit one around $100.0 US should do.
Easiest way to backup is to purchase an external drive larger than your laptop drive in size. (I think for a G4 machine you're going to need a Firewire (aka:IEEE 1394) connection to that drive) Format it via Drive Setup (You want the Mac OS Extended format)
If you leave the drive connected you can use an automagic backup application scheduled to backup as often as you like, backups that aren't kept up are just a bit more than useless (there were some good free ones for OS 9/early OS x - I like LaCies Silverkeeper (works on any hardware).
If this answer was helpful please remember to mark it accepted.