Fox International Electronics had a bunch of stuff, back in the day.
Here are some links, don't know if they're still available:
Stylus.
USB Cable.
Cleaning Kit.
AC Adaptor.
You can get batteries rebuilt, too. Could probably do it yourself with a little research -- just remember that you need to keep the bit of electronics that is attached to the old battery pack.
Luck.
m a r
EDIT: and there's
this...