Sorry to say, but those are probably going to be disposables.
You could try a local tool and die shop.
You could also probably do it yourself. Assuming the bearings are just a press fit, with a "C" clip retainer on either side of the shaft.
http://www.bocabearings.com/
Pull the bearing out and mic it. Boca has some high grade stuff that I'm sure would work, and would probably be better quality than what it came with.