What's your SU version, and What QGIS version? There used to a shp tool very long ago. Also have just found this, which may be a solution, or a path to one: https://forums.sketchup.com/t/importing-shapefiles-shp-to-sketchup-skp/59032/10 I can't help you more than that at moment. Haven't used SU for a while so it looks like folk are still doing interesting things with it.

Extracting models is against the TOS for Google Earth. Extensions, like PlaceMaker, can extract 3D buildings from OSM but these are only good for mass models.