Calendar over here in the UK is 2200 for both engine and airframe. There is an 'intermediate' 12 year calendar review you can do, which means stripping the whole machine apart, which I am led to believe is about £20-£25k, so if your TT hours are quite low, its worth doing.
What sort of extension can you get? I can't find any details on Robinsons web site but would be interested to know more.