You are seeing a Basemap on your Nuvi "gmapbmap.img"
Now you need to load a detailed map "City Navigator 2014.20" this will be "gmapsupp.img" or "gmapprom.img"
Have a look here [Only registered and activated users can see links. ]
If you have Lifetime Maps on this Nuvi then use GarminMapUpdater.exe to get the update from Garmin Servers.
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