Possible to play sprint nav prompts through my bluetooth?

[asquad]

I have a motorola bluetooth speaker I dont remember the model number, but it clips to my visor. I am wanting to have my sprint nav turn by turn prompts play through the bluetooth. I mount my phone on my dash while I am driving and if I am on the interstate with my radio turned up even a little, I have a hard time hearing the prompts. If the prompts start and I hit the button on my bluetooth, it will direct it through the bluetooth, but that promp only. The rest just continue through the phone. Any ideas on how to direct all the prompts through my bluetooth?