Check out iProtect from
http://www.digital-concepts.net/cgi-iprotect.html
If you ask real nice you can probably get a deal on it. That page/site hasn't been updated since like 1999... but the iprotect module kicks ass for password abuse.
On the other hand, you might also want to make sure you get the latest version of your processors scripts. I pretty sure that CCbill & IBill both had some problems.. either with their scripts or their auth codes getting stolen or something.
In fact, if you use CCbill or IBill with pw management, you should just ask them to issue you a new auth code & make sure the script is the latest version.