Nelson family

I am trying to locate my great grandmother's family. Karen Kristine (Carrie) Nelson was born in Norway 1859/1860. She & her family emigrated to the Ladysmith, Wisconsin area before 1879. The 1880 census for Barron Co. Wi. list her as 20 yrs. old - born in Norway & living with her husband Knute J. Oleson, 1 year old son Joseph & her brother - Adolph age 12, born in Norway. (Knute was born in Wisconsin 1849.) Family members claim she had at least 1 sister - Ann - but have no idea where she was born or what became of her. She may also have had a brother Thomas. Some family members (now deceased) claim she had as many as 10 siblings all born in Norway. I have absolutely nothing on her parents. I do not know where she lived in Norway other than the Valdres area. Any suggestions or help would be most appreciated - Laura L. Jones