Contact these guys and see what the say about rewinding yours.
http://www.smithae.com/cando.html
http://texasindustrialelectric.com/home.asp
http://www.alternatorparts.com/
Tell them you have a KA or Quest alternator that you want rewound to output at least 160 amps. Get photos off ebay and email front and back views of the alternator so these guys have a better idea of whats up.
If you absolutely have no options then this is a last resort:
http://forums.nicoclub.com/zerothread?id=131961