Norwegian ancestory mystery (Eastmon)

I would like to obtain a copy of my great grandfather's (Albert Eastmon) birth certificate. The main reason is so that I can find out who his birth parents were. Albert migrated from Norway (Tolga) at a young age to New York and arrived a few years later on the "Turon" in Melbourne in1858, via New York and Liverpool. He died in a mining accident at Mount Malcolm, Western Australia 1897. His wife was Isabella Crozier (m. 12Dec1867, Clunes, Victoria). I believe Albert was born in Tolgen (Tolga). Unfortunately I have not been able to find out details of his birth. Who should I contact? Kimberly Smith, Mont Albert, Victoria, AU 3127