Snuffer is the word your looking for

http://gobarefootstudio.com/
www.goodaldesign.com
www.nacrasailing.com
http://falconmarinellc.com/

not likely another manufacturer snuffer will fit your hoop, your local sailmaker should be able to copy your old snuffer pretty easily and that will be the cheapest way of replacing it, if you do replace the hoop and order a off the shelf replacement the SNU is highly regarded but all the major manufactures will have something for you.

hth