Kings yesterday, paupers today and kings again tomorrow. That's the way it goes when your economy is dependant on demand for export minerals.
World demand for our exports has about halved and prices for that have halved also. So its pretty bad for the Aussie economy overall. But we have been down this road before and we will bounce back when the world economy picks up. Its not like the USA where the fundamentals are fatally flawed because of their financial system. Times are going to be tough in Oz for a while (maybe years).
No one will want to buy the $Aussie, and Thailand has the ability to prop up their currency for a couple of years yet, so the Thai Baht/ $Aussie is likely to be pretty bad for a while. The wild card in there is the crash of the $US. When that happens its likely a lot of money will go back into countries that actually produce things other than paper money and the Thai reserves of US currency to back the baht will be virtually worthless.