Where to get another c500.1

I'm running a carbon series 500.1 to run an Alpine R type 12"dual 4 ohm subwoofer in a slot ported enclosure and it feels awesome now I have another Alpine R type sub and want to install it but I can't find another c500.1 carbon series to run the other 12"sub.
I live in Australia and can't find anywhere that sells the c500.1
Can anybody help me