The problem is you lost your model number. The map update went wrong probably.
Actually you have a basic 37xx, no bluetooth and other features. If you havent a backup of your NV ,it will be complicated to restore it.
You can edit your GarminDevice.xml before updating maps and get 3790 files, but you'll have to do it every time you want to update it.
Just GarminDevice.xml is needed in sd in a Garmin folder to update maps with Mapupdater.
To have back 3790 features like bluetooth and voice commands you can transform it in 34xx or find someone who can use another 3790 NV to prepare needed region to dump in your nuvi via sd.
Or if the Nuvi is still on warranty you can send to Garmin to restore it.

A good advice : dont use Nuvi to update maps via Mapupdater or to update firmware via Webupdater, please use sd.
Read some threads in tutorial section , your Nuvis will thankyou