Does anyone know where I can get them from?

I would not have a clue. Start with Volvo Main Dealer, then once they've said no, consult the specialist garages. There's a couple of places breaking 360's down in Sydney, but it'll mean postage charges etc.
Maybe phone around every car breaker in the book, one is bound to come up with a 360 sooner or later.

Getting your old ones re-con'd is always possible too, there is Volvo owning chap in the UK who does it, not sure about over there though!

Should be a kit available and refurbishing injectors isn't normally to much of a big deal. What brand are the injectors?