My goodness, you're going to have your hands full! THat's a common fault of pet shops (you know, other than selling them as snake food). It's truly hard to find a place that actually takes proper care of rats.
Coco having kittens should be a great experience for you and your child though, and rats generally make incredibly mothers.
Yes, I'm in the US, but here is the address to the Australian Rat Fanciers Society:
Who knows, you may find someone there who could help you place some of the babies, and at the very least you could make some contacts and meet some other rattie people
It also has a good links page of many other Australian rat organizations and personal home pages.
Here are a couple general links about rearing babies, and tips on how to find them homes:
