I'd love to see the rest of the story, Rao. Power Girl has become one of my favorite characters (mostly thanks to Johns) and I'd love to see her full origin. I've read about it but I've never seen the comic.
Her "first appearance" and her "origin" are
not the same story.
What you see in these two pages is all you get for her introduction. She showed up; she punched villains and bickered with all of "the guys," including Superman; and that's it. No close relationship with Kal or Lois; no adoption; nothing.
Her "origin" was told later over the course of three issues of some other title. I don't remember being that impressed with it. The recent re-telling was a bit better.
The odd thing was that the first "origin" story was really just a re-telling of her own recollections, as possibly planted by the spaceship that brought her to Earth. When you read it up against the Arion retcon; and then the recent back-to-Earth-2 re-retcon, you realize that she has
never had a real origin story. The first one feels just as fake as all the other ones she has had.