Have friends who spent £2000 fixing up their run-over cat which died 3 months later. £600 for a pet is acceptable in my book, if you have the money. We used to waste that amount every month in the pub, before we stopped drinking completely. If our pet cockerel (who lives in the house) was ill we'd throw everything we had at him to fix it. Unfortunately we haven't got a lot to throw at the moment.
I'll enquire about pet insurance with the vet.