Blue&Me can't stream music over Bluetooth. Fiat chose not to include the required protocol, A2DP, in the Blue&Me specification.
There's no easy fix. If you want selectable music with Blue&Me, put it onto a FAT32 formatted memory stick in .mp3 format; you'll be able to choose the track you want using the steering wheel buttons.
On a 2012 car, the best value for money way to address this shortcoming is probably to fit an aftermarket head unit.