If you want to use WP as your primary script you should install it into the domain root (rubilon.com directory). This is easy, even with only FTP access. Just rename the current directory to rubilon.old, create another rubilon.com directory, and install WP into the domain. You’ll still have your already uploaded files in the .old directory on the server and can move the ones you want to keep into your site once you have WP set up (saves re-uploading). Once you have everyhting running correctly, delete the .old directory to free up space.