hopefully you get this, it's been awhile since you've posted.
you have 10.4? 10.4 came primarily on DVDs unless ordered otherwise. a g3 ibook is only going to have a cd drive in it, so it will never boot from that disk. you can obtain 10.4 cds from some places online (i won't get into legality - you do have a legit copy of the dvd so is it ok to download a cd version?)
the password also can't be changed unless you boot from an installer, what i would do is make an appointment at a local apple store if there is one, they'll gladly boot from one of their HDDs and change the password/help you online/change the time and date for free.
hope this helps.