Congratulations!!

First, get the top dirt dug off and get down to subsoil(is that possible in Illinois?). Then build it up with rock or gravel to your desired height-preferably several inches above the surrounding terrain. You for sure need to get the stumps out of there, they will rot down over time and cause all kinds of problems.

If there is any way you can scrape up the cash, now would be the time to cement it.