From a high to medium level trust enviroment.

hey guys, i wrote all my code on my computer so i had a high trust level, after ftping my site and database to godaddy.com i realized they have a medium level trust enviroment.... i called the tech support and they said they were sorry but they couldnt change it for me... heres my code. any idea how to get it to work in medium level trust?
I am trying to create a new directory where all of a users upload goes. The folder is created dynamically when the upload page loads....
   string username = User.Identity.Name;

        string UpPath;
        UpPath = "~\\Users\\UserUploads\\" + username + "\\";

        if (!Directory.Exists(UpPath))
        {
            Directory.CreateDirectory("~\\Users\\U ...