How to get concert tickets when not in Japan..?

[Estella]

Hi there
I'm sure this is something people have asked a lot before.. but I have no idea so I am in dire need of your assistance..

A friend and I are planning a trip to Japan for January next year.. so I want to see if I can see Ayu's Countdown live while I'm there..
So is there anyway to buy tickets for Ayu's concerts like online and have them posted to me before I go (I'm in Australia) or pick them up at the venue on the day.. or do I have to be in Japan and physically buy them.

Also when to the tickets for Countdown generally go on sale? And the price??
If anyone can guide me through the ticket buying experience I'd be very thankful!!

Thanks so much
Estelle