You'll not likely find a new one, so a donor or proper repair will be your options. But repairing poly plastics are difficult because nothing sticks - at least for any length of time.

I have used this on door panels, plastic dirt bike fenders, urethanes, etc. It is simply amazing and works as advertised: http://www.urethanesupply.com/Airless-Welders-1/Micro-Weld-80/