If you want to buy something like this from a shop in the USA or UK, try using a Freight Forwarder service.
EG: I have used one called MyUS, which give me a freight forwarding address in the USA and also one in the UK.
There are a few others.
You simply order online using your Freight forwarding address in the relevant country. They receive the item, and ship them on to you for a freight and handling charge. Because they specialise in this service, they can sometimes have quite reasonable shipping prices, but not always, because some online retailers have their own very good shipping arrangements, and some subsidise the shipping. It pays to check your options
But when the vendor does not want to sell direct to Australia, freight forwarding services are often a good work around.