Add User after PayPal transaction

Here is my current setup:

  1. Wordpress site that requires login.

  2. Yii Framework application that requires separate login. (Different user database).

For now we have been manually adding identical logins for Wordpress and the Yii Application as the program has few users and is in beta.

We have now setup a PayPal button that charges user and auto creates a Wordpress username and password. As of now there is a notice that says "your account will be fully active with in 24 hours" and we manually add the Yii application login and send them those credentials.

Is there a way to add the exact username and password created for Wordpress after PayPal transaction for our Yii Application?

Best way would be to extend wordpress to duplicate the login or make Yii use the user table of WP.