You can indeed use digital globe data to get a rough height. to do that, geolocate your model and once you grabbed the area, go to your tags and turn on location terrain.
But it won’t be very precise.
There’s a more complicated but more precise way, since you have a dwg topographic survey.
Using autocad, there are LISPs that allow you to move automatically your altitude points, based on the “LEVEL” parameter, along Z axis. You can then import it in sketchup and use a triangulation plug in, such as TIG’s triangulate points ( https://sketchucation.com/forums/viewtopic.php?f=323&t=34232 )
otherwise ask your surveyor if he can send you those points in 3D instead of the 2D plan you attached
Another way would be to draw the contours yourself from the informations you have in your dwg (let’s say every 10cm height), and then use create from contours inside sketchup. Not the shortest way but effective if you don’t want to throw yourself into those LISP commands. (kind of fun too ! )