you should be able to just strip off some of the insulation and twist it together, that should work. (maybe with slightly less range, but still enough)
better solution is to solder it back together
better solution again is to replace the antenna altogether, carefully open the receiver, and desolder the existing antenna and put in another. make sure that the solding iron that you use is not too hot (maybe 15a), because you are working in a circuit board,
even better solution is to get someone in an electronics shop or someone who know how to solder to do it for you...
GTB SS + 13.5 & 10.5