Ouch, that's a harsh break to have on an exclusive toy.
So far I haven't had much luck using superglue on any sort of stressed areas of plastic... it works fine for cosmetic fixes (side mirrors, head crests, etc), but anything under stress like a joint, the glue just snaps right off. I dunno, maybe I'm doing it wrong or something. Could be I need to let it cure longer. I used superglue on one of the armor tabs on my G1 Jetfire, and it broke the first time, but is holding so far the second.
Maybe you could rig up something more permanent as a splint. Tape may leave a residue on the plastic, you could perhaps try some of the clear elastics they use in the Hasbro packaging.