parents of Tarje Jorgensen and of Guro Tarjesdatte

I have found back to my ggg- grandparents but am stuck with the family tree any further on this side. My ggg-grandparents were Tarje Jorgensen born around 1820 in Nissedals and Guro Tarjesdatter, born 1835 in Vinje. In the 1865 census they lived on Lien in Vinje and had two children: Jorgen and Gro. Could anyone help me out going further back or give me a lead as to where to look? Thanks.