how can I add a city to my navigation in my infinity QX56?

My navigation does not recognize the town I live in. How can I add my town? I have a 2005 infinity QX56 with the navigation system under the passenger seat. It has a disc in it. It reads Vancouver and Victoria but not Nanaimo. The arrow on the screen appears on a blank background. Could I insert a disc from another vehicle's navigation that reads Nanaimo as a town? Would it matter if the make of vehicle was different?
Thanks