Sounds like you are connecting to the guest wireless network.. There should be another wireless network that the Cisco router is broadcasting that is the "main" wireless network. The password ***** the guest network is set within the Cisco administration interface.
How do I get that password?
You need to know the administrator password ***** the cisco router. You could then plug into it with an ethernet cable, enter the IP address of the Cisco router into your web browser, and login with the administrator password.
You can also reset the Cisco router and set it up from scratch using the default password. There should be a pin hole on the back of the router to reset it.