loking for surenames helseth,hilseth,helles

I am trying to locate family in either Oslo or Hellesylt. My grandfathers name was Edwin Helseth, he had a sister Anna Helseth. Their Parent came from somewhere in Norway. Their names : Ole and Signe Helseth. I found a picture of them in my fathers belongings. If you can help me locate and information or distant relatives it would be wonderful. They settled in Minnesota USA