Bluetooth to bluetooth hopping

Hi my question might sound a little weird but its just a small pet project that i am working on and am hoping for some advise from people more knowledgable than me.

I can't afford a full fledged bluetooth car handsfree (i.e. a car stereo bluetooth adapter which automatically transfers an incoming call on your mobile to your car speakers. Well since i can't afford one i made one.

The principle that i used was very simple, took a $15 bluetooth handsfree, dismantled the casing, and cut the speaker wires. I soldered a long wire to the handsfree pins and the other end to a 3.5mm jack which i plugged into the AUX-IN of my cars music system. The handsfree i then stuck on to my steering wheel with the mike facing the driver. The way it operates is that when i get a call on my mobile, i have to active the handsfree and change the setting of my music system to AUX and the audio is thereafter transferred to my car speakers.

Now there are two problems with my design. The first one (and the question relevant to this forum) is that of the wire connecting the 3.5mm jack to the handsfree set. I want to get rid of this wire instead of having it untidily taped along the side of steering wheel and the glove all the way uptil the music system. The advise that i'm looking for is some direction as to how i can get rid of this wire.

I was hoping to do a bluetooth hop between the bluetooth hansfree and the AUX-IN. In other words get a bluetooth dangle (or a similar other bluetooth tool) which connects to the AUX-IN, this dangle is paired with the audio out of my bluetooth handsfree (this is what i don't have any clue how to do), such that when i get a call and activate the handsfree, the handsfree acts as the receiving mike, and the audio does a hop from here to the dangle and gets played on the car's music system.

Can anyone please help me out here or at least point me in the right direction?

The second problem which i have with my existing set up, (which probably is the subject matter of a different forum - i apologize in advance) is that my music system is an older generation one. It does not have a remote and i have to manually button toggle between the different modes (cd-fm-aux). what i want to be able to do is cause my activating the handsfree to automatically switch the music system to the aux mode. can this be done through the blue tooth dongle itself? Again can someone please point me in the right direction?

thanks a ton. O and just to give some background, I'm a corporate lawyer with an interest for diy and tech, and a habit of dismantling things. however not having the necessary electronics/programming background, means that i'm fairly cramped in my understandings and limited in that sense. I would request any response to be as simply worded as possible. thanks again.