I don't know, man... I'm not so sure a bit of topsoil will help what you've described. If the equipment packed down the topsoil, you've now got less drainage (due to the compaction), as well as sloping issues. Hopefully a bit of topsoil does the trick, but worst case I'd look at something like a French Drain to get some real/proper drainage out of the area. Especially if it's between your houses, because that's just more water around your respective foundations.