Help Voice Dialing, BT and Toyota


I just got a 2008 Prius with BT. Phone connects and calls fine through the car's directory. Is there a way to get to the Android "Voice Dialer" from car's BT? I really don't want to duplicate my directory. I can't seem to bypass the car's system and just use it as a big BT headset.

This system is probably the same in all Lexuses and Toyotas, so anyone has figured it out, thanks!