I am sure Amy will fit in very well! Kids are kids no matter where you go and for the most part they are pleasant and accommodating and kids coming from overseas usually have a good honeymoon period. The kids dont worry about the tests here at all - they are usually considered more of an inconvenience than anything else! They do take up the best part of the week though and unless they have changed things to go along with the new national testing regime, they are incredibly broad so there is listening, speaking as well as the usual comprehension, writing and maths papers.
As for living costs - well we are a retired couple these days so our costs are going to be somewhat different but ball park rental here is about $450 a week - average mortgage would probably be similar or a bit more but we dont have a mortgage so I dont really know. Our groceries (and we dont hold back) come to about $200 - $250 a week I would think. Broadband, landline phone and cable tv (free to air channels via Transact) $75 a month, electricity anywhere between $120 and $200 a quarter depending on the quarter (we have solar hot water and slow combustion stove where DH scavenges for wood otherwise both would cost us a lot!). Water and sewage anywhere between $150 and $250 a quarter depending on time of year. Mobile phones about $60 a month, internet ISP about $50 a month, petrol hovering around the $1.50/l mark at the moment - goes up and down depending on whether it is pay day or not. Parking in civic $10 a day or bus fares at $2.20 a single trip. Private health insurance $240 a month. Average wages in Aus are about $60k just to put all that into perspective. No idea on child benefits etc other than that they are means tested. A good latte will cost you about $4
