Headlight assembly is sold as a whole piece. You can find an aftermarkt one at eBay at much lower price than at a dealer.
If you think glue would work and make it last for a while, you can get J B Weld at a auto parts store. There are a few kinds with little difference. You can choose the strongest one and try. This glue should make the bond for a while. However, the real right fix is to replace the broken headlight assembly.
