So far, none of you are close other than the fact that it came from the 1970s. I would have figured that part of the interior would have given away the make by now...
Hmm. The seat-back pull mechanism is saying VAG to me, and the dash looks similar. I was going to say it was an early Audi, perhaps even a pre-production ur-Quattro, especially since my Dad's one had really nasty seat patterns. But that car didn't have the split front window. So I'm going to say it's a VW Scirocco.