Is there a way to use an Android tablet as a wifi handsfree device? My situation:


Android (4.0.3) tab hooked up to my car stereo using the headphones connector.
Android (2.3.5) phone (HTC Desire HD), which I use to call, text, browse, etc.


Since my car stereo's Bluetooth device died I thought I could use the Android tab as a audio relay device. Problem is: the tab has no Bluetooth. It has wifi though.  

Is there any way to use an Android device as a handsfree adapter over wifi? Some kind of wifi relay between the phone and the tablet, perhaps?
Does the tab has USB port. How about adding an external custom BT device. BT device talks to android app on tab via any serial library for example scm (http://www.embeddedunveiled.com/scm-wiki).