Guro was actually the daughter of Jørgen Olson -- therefore she should be called Guro Jørgensdatter. Jørgen was married to Ingebjørg Larsdatter in 1743 so is therefore highly likely to have been Guro's mother. This information is from "Odda, Ullensvang og Kinsarvik i gamal og ny tid -- Bygdesoga - V/2" on the pages for the Instanes, Ytre (Ystatun) farm in Kinsarvik.
"Joren" is not actually a male name in Norway so be careful of your spelling for that.
The surviving parish records are available online now at the Digitalarkivet website. If you don't find a mother's name listed for Guro's birth/baptismal record (yes, there actually were years when some of the earlier parish records did NOT record the mother's name with a child's birth) then you might have to use the evidence of an earlier marriage record for her father and then research into WHEN Ingebjørg Larsdatter died because she is almost certainly mentioned by name in her own death record.
You have tried the scanned parish records at Digitalarkivet website?