You have an older tractor and I'm sure Deere won't be carrying any in inventory. However, you should contact a Deere dealer since there may be a dealer with one in stock somewhere...I doubt it, but it can't hurt to ask.
While the dealer is searching, I suggest you go online and look for an aftermarket loader. There's a reasonable chance a manufacturer may make on to fit your machine. Just read the specs carefully...you don't want to damage your old iron with too big a loader.
This isn't going to be cheap though...unless you find a used one, or a dealer who just wants to get rid of an obsolete loader, you're going to spend $2000-$3000.
Might even be time to just upgrade to a newer tractor.
Good luck!