looking for information on the Hofstad family

hi my name is john paulson, i'm looking for information on the hofstad family. I don't know what part of norway they came from??? i have a family tree book done, but there are some things that don't make sense to so i was wondering if anyone could help me find the answers i'm looking for. my great grandma's maiden name was Anna Hofstad. her father's name was torsten hofstad, and his father's name was erik hofstad. thanks, john