Knut Nielsen Rollag

Looking for information on Knut Nielsen Rollag, wife Margrit and daughter Gunnild emmigrating from Tinn Norway in 1848. I believe they went to Wisconsin where daughter Gunnild married Ole Oleson and shows in the 1860 Census for Berry, Dane, Wisconsin. I have not been able to find the ship they immigrated on or where Knut and Margrit went after arrival. The immigration record is at http://gda.arkivverket.no/cgi-win/webcens.exe?slag=visbase&sidenr=1&filnamn=em08261837&gardpostnr=318&personpostnr=318%23nedre