Here's what Caster lists for the Australia distributor. If they are anything like CasterUSA , parts should be pretty easy to get even if you have to get them direct from your distributor.
JPM Racing
Unit 14/116-118 McCredie Rd Guildford NSW 2161 Australia
Phone:61 2 9799 8181
Fax: 61 2 9716 7525
email :jpatane@jpmracing.com.au
website :
www.jpmracing.com.au
A lot of Mugen (and other Mugen-inspired cars) parts work also. I don't know exactly what parts DON"T fit... but I think most do.