I searched on eBay and asked a seller which item I needed. He pointed to this one:
http://cgi.ebay.com/NEW-Fire-Hose-Br...QQcmdZViewItem
or search for item 7769289291
It has a male NST end to fit my fire hose, and a female NPT end that the seller says will fit the PVC threads. I am going to buy one, I will let you know how it works.