That radio is not that old, regardless of whether it's being made or not. You can get the part directly from Yaesu, but I don't know if they have a minimum order.
A VERY quick search at Google, using "yaesu parts" led me here:http://www.technodaddy.com/vx5faq/faq.shtml#How%20can%20I%20contact%20YAESU%3F
A: Yaesu U.S.A. is located at 17210 Edwards Road Cerritos, CA 90703.
Tech Email: email@example.com
Parts Email: firstname.lastname@example.org
Have your model a nd serial number ready.
Hours are 800 to 1700 PST
You might look the radio over carefully, how is the case, rubber inserts, antenna, battery? Do you need a new antenna?
You may need a couple of other things, and IF they have a minimum order, you might find enough stuff to fill it!!