That is an internal IP Address, anyone outside of your home network cannot do anything with it. For someone else to remote into your network you would need either a static external IP or a dynamic name translation service like dyndns.com. I Recommend you call linksys for their customer support, they would be able to help you best.
Yes go to your start programs and look for the cisco connect that you used to install the router, or use the flash drive you used. In there is a selection for guest network and there you can set the guest password