How is the drainage right now? If you have good drainage and the soil is at about the level of any concrete, then do not bring in more soil and ruin it. If you have good drainage and absolutely need black dirt, whatever that is, then remove some of whatever you have now first to account for the new dirt.

Whether you get new dirt or stay with the current dirt, you should get a soil test ($25 from Logan Labs) to see what the chemistry is telling you it needs.