Cheapest around and best prices according to CamelX3. These router are 4K ready to stream your 4K movies over your network with no lag
220v compatible according to google so you would need a US->AU adaptor which you can get from Jaycar for a few bucks
You can buy compatible power supplies from a lot of places as well for ~$20 (so you don't need to use a bulky adapter). Just make sure tip shape and output voltage are the same, and that it has at least the same amount of amperage as the original supply.