I'm sorry to hear about the breakup. A small change is usually necessary after something like that happens.
I would agree that Style in Play is "summery" but so is Mugler Cologne.
Some suggestions for Autumn are woody, dry scents. I don't know what the climate of an Australian Autumn is like but if it gets cool, then try these: Gucci pour Homme, M7 by YSL, Dzing! by L'Artisan, and Rive Gauche by YSL. If it is warmer then you can stick with what you are thinking about buying anyway. Good luck!