No, you do not need a new radiator yet right now. You have a few options. Sure glue the nipple back on. super glue or epoxy a nipple in the hole and reattach hose. I would stay away from using any type of threaded device as it is brittle. Remember this is not pressurized. Flow goes both ways but not under pressure. I would find a nipple that barely fits in the hole and force it in being careful not to crack it. Then reattach hole. Check it every week or so and see if it is leaking. When it does time to replace the radiator.