My talon air tank is leaking and no longer holds air

I’m pretty handy but before doing something I’ve never done I wanted to see what is needed and how hard it is to repair.
My tank started to leak around the brass fitting. I tried filling again and the leak got worse and a piece of yellowish plastic came out of the end. It currently doesn’t hold air. I’d probably not try filling after the piece of plastic came out. Any direction or suggestions would be great! Thanks