Whale and welcome to MoveToNZ.
Sorry, can't give much info on Christchurch as I've never been there but would suggest having a look at some properties, whether you want to rent or buy. If you get the job in Timaru and will be moving to NZ shortly you could select a few places to see while you're down there. Buying or renting straight off the Internet is not advisable as things aren't always how they first appear so it's better to see for yourself. If you look on the
Master Website List under Real Estate there's some property agents' sites where you can research what's available for rent or to buy. Under Travel and Transportation/Accommodation you should find some websites to search out places to stay.
Hopefully though, some of the Christchurch crew will be along at some point to give you 'on the ground' info.
with the job interview. Let us know how you get on.