This script doesn't have the rank functionality built in, and it is kind of counter to what my script was designed for to have the admin register the accounts.
If you want a login script written for you exact specifications you can contact me here
http://watdaflip.net/contact.php
and I can give you a quote on a price for the functionality you want. However I do not accept **** live credits (nor do I accept bits of string), as payment. I only take actual US currency sent via paypal or another method of payment we agree on.