Where am I ?

If you have the WiFi-only iPad your location is determined by the location of nearby WiFi routers. This is done by using a Apple location database which contains the MAC addresses of routers and their physical location. A MAC address is a unique number which is built-in to all network devices when manufactured. The Apple database is built and updated by Apple GPS-enabled devices (primarily iPhones) actually seeing your router and then adding/updating the router's location in the database.

Bottom line: Your Router is not yet in the Apple location database. It hasn't been seen yet and added to the database. There isn't any problem with your router or your iPad.

There is no manual way to add it that I know of. You can invite a friend over who has an iPhone.