It sounds like the Bluetooth module is already connected to your Arduino Uno along with the motor driver shield. I recommend focusing on getting the motor driver shield to work first before adding on more devices like your Bluetooth module. If you haven't already done so, can you remove the Bluetooth module and run the demo example on your Arduino Uno with the shield connected? Please let me know the results and post pictures.
By the way, since you are powering the Bluetooth device from the Arduino Uno, you should double check to see if the Arduino Uno can source enough current for your Bluetooth module.