Roald Amundsen (1872-1928), Norwegian Explorer

Can anyone tell me who were the parents and paternal grandparents of Roald (Raold?) Amundsen (1872-1928), Norwegian Explorer? I have his full name as both Roald Engebreth Gravning Amundsen and Roald Engelbregt Grauning Amundsen. Apparently he was born July 16, 1872. One source says he was born on the family estate at Hvidsten, which lies between Sarpsborg and Fredrikstad. Another says he was born at Borge. Another says "near Oslo". His uncle (his father's brother?) - Amund Amundsen (born 1843) - emigrated to New Zealand in 1875 on the 'Fritz Reuter' (from Hamburg) with his wife and children. Amund and family are not found on the emigrant list at Digitalarkivet, but came to New Zealand after spending some time in Sweden. I am trying to find out about the common ancestors, and family background, as I have been given a manuscript written in the 1960s by Amund Amundsen's granddaughter (now deceased) which recalls her childhood memories from 1897-1912. I would like to publish this manuscript and am hoping to include some family tree info, especially as the author makes reference to the family's correspondence with Roald Amundsen immediately prior to his disappearance. I would also like info about Amund Amundsen and family. He emigrated with his wife (Elise Larsdatter, born Norway 1848) and four children (Carl b. Norway, age 8; Lars Wilhelm b. Norway, age 5; Annie Louisa b. Norway, age 3; Albert b. ?Sweden, age 9 months). Several other children were born in New Zealand. Amund also had a sister who emigrated to Australia who is referred to as "Mrs Heiberg" in the manuscript.. Any information about these people would be greatly appreciated.