1999 6x4 utility, can't find parts

I'm new to forum so apologies if this isn't being posted in the right spot.

I have a 1999 6x4 utility gator with a Kawasaki engine. I need to locate a replacement alternator for it, but this is proving surprisingly difficult.
I've contacted John Deere directly and they've been of little help.

The basic issue is that operating the gator does not recharge the battery. Inevitably, within a few weeks, the gator needs a jump.

I'll buy a drip charger in the mean time, but hate to resort to that.

Thanks in advance.