1982! Damn, that thing looks better than most cars from the early 2000's around here. I agree with superfuel's suggestions, especially that top bar poking out. On an 1800 mile trip to and from canada to pick up my CBR, we were towing a trailer that had a straight up door like that, and we got about 18-20 mpg.
At the speeds we were doing, the car should be able to get high 20s maybe low 30s, then add the trailer, and it shouldn't hurt too much, but it did. The car got better gas mileage with the bike on the trailer!
Fix that aero! Unless you don't do much high speed driving.