Why do you want to add top soil? How much did you remove with the sod and did you compost the sod. If you still have it and can pile it up somewhere and cover it with black plastic in the spring so it heats up real well, it will decompose into some great organic rich soil in a year or two. You added organic matter already, if you didn't end up with a big hole, I would save the money and not add any "top soil". Top soil is an unregulated commodity in all but one or two southern states, I could be subsoil, it could and usually is very weed laden, it could be clay, it could be almost anything, including 1/2 or more composted yard debree. If you must add more, I would suggest either piling all the leaves you can and pine needles, shredded newsprint etc and leaving it until spring, then turn it in as well option 2 look around and see if any of the places in you area that carry bark mulch also have mushroom compost. If they do I would use it instead of top soil, it is a regulated commodity. I am an environmental engineer as well as an advid gardener and amature breeder. I admit to buy a truck load of top soil, but that was to fill a large hole in the ground where a tank had been removed, and once to see what it would be to fill a box, it was junk clay with lots of weed seeds, just like I thought it might be. If I were you I wouldn't waste money on "topsoil".