If you have decent soil there now, you can reseed without tilling it
up. Rent a slice seeder, which is a gasoline powered machine that cuts
shallow grooves in the soil and drops seed in them. It's one of the
best ways to get good germination. Two people can easily put one in
the back of an SUV, as long as its a small one, which is the most
common kind. You can put topsoil just in the areas that need it.

Of course, what you're up against now is it's late for Spring seeding
and Fall is by far the best time. Now you'll have to use lots of
water, so I hope you have a well and don't have to pay for town water.
Also, weeds will be a much bigger problem