Leaking Air Valve

Hello all, Today my water system sprung a leak just inside where it comes into the house from the well. Attachment 37361 (http://www.doityourself.com/forum/attachments/plumbing-piping/37361-leaking-air-valve-dsc_0939.jpg) It is a steady stream of water coming out, like it is peeing. I plugged it with a toothpick, for now.