iBook G4 battery charging problems

My sister recently gave me her iBook G4. She's had it for a few years and it's been working smoothly for the 4 months I've owned it. Now all of the sudden it's stopped charging. I had a Macally charger and whenever it was in it made a weird, small buzzing noise. We went to the Apple store and it did turn on with an Apple charger. It had gotten to the point where it wouldn't even turn on for a few seconds with the other charger. We bought the Apple charger and took it home so I plugged it in for a few hours to charge it while I went out to see a movie. When I got home I turned it on and it wasn't charged any more than it had been when I left, at about 3%. I really don't know what's wrong at this point. I'm not computer savvy and especially not with Macs, this being my first one. Does anyone have any idea what's up with this notebook?

Bump. Can anyone please help me? Do you think I need a new battery?

New charger same dilemma I would bet it's the battery.