Welcome to the world of "geographical restriction" pricing. Yes, it seems the rest of the world is indeed getting "special" pricing from Mouser (and an increasing number of other retailers are starting to do this too, apparently), which has nothing to do with exchange rates, it is simply opportunistic pricing (we will charge in each market what we think we can get away with).
One way to get around the websites picking up your country from your IP address is to use a VPN with servers in the US (if that's the location you want them to think you are coming in from.) Your next challenge will be to see if you can get them to ship outside the US if you use the US website to purchase from. If not, you may need to use a postal forwarding service, or get a friend in the US to forward it on.
Sucks, but that's the price you pay for not being smart enough to be born an 'mercan. Good luck.
But don't feel too bad. It looks like Mouser felt the 'mercans were getting too a good a deal, and so have put their prices up too (considerably! $36.49 -> $48.95 > 34% increase!) I wonder if the original $36.49 was simply a pricing error, or whether it has been "suggested" to them by the suppliers (i.e., Arduino) that they fall in line and stick closer to the list price, at least while the launch is underway.
I'd kill myself before paying the au.mouser.com prices, though. Someone at mouser must have had a bad shrimp off the barbie, or got bitten by a rabid koala bear or something.
Edit: Interesting link