You can get it at 'pets paradise' for $10 for a 1lb bag. That does however get expensive over a period of time. Where in NSW are you? If your near Camden there is a good feed store there that sells timothy hay in a bale. You could also go to www.yellowpages.com.au and search for ''hay' or ''feed stores''.
Feed stores usually have hay. You want a grass based hay, green, soft and fresh with no sharps pieces in it. It must smell nice and fresh too. Hay should be fed 24/7 in unlimited amounts. If you cant find grass hay suibstitute it with lucerene which is at all pet stores ( I find in my area). Only for a few days util you can find grass hay.