That sounds about right under the circumstances. If you want to greatly improve fuel economy, the best place to start is the transmission. That requires a significant financial outlay, though, and can only be justified if you plan to keep the car for a long while..
Jack Travis, E-Series Acting President
1989 Ford Fairmont Ghia turbo/GL replica (underway)
1994 Eunos 800M
1990 Ford Laser S