Go immediately to an Apple Outlet and talk with a tech on-site. Explain the issue and what you have been seeing. Something on the mobo is definitely toast from your description.
If you elect to have it fixed, make very certain that they know that you need the data from the HDD. Make sure that they know that part of fixing the lappie is to create a disk of the data files that are on it.
If you don't care to have the existing lappie fixed, you can get a local tech to remove the hard drive and purchase a USB enclosure for it. Purchase your new computer and plug in the newly enclosed HDD. Remove the files that you wish to retain.
Learn to make back-ups of your critical data. Do it every month on the same day. Helps you to remember to do it. I have an appointment set in Outlook to remind me to do back-ups. It helps.
Do not drink wine close to your lappie any more. Apples don't drink.
Oh! If you decide to replace your iBook, get another iBook. Your data files won't necessarily be readable from Vista.
Let us know how it goes.