I think your only other option is to get a version of Android called CyanogenMod running on your hardware. If you do find a custom version of CyanogenMod designed for your hardware, you can go from there with respect to adding features. But, fair warning, if you get good enough to add features, then you will essentially have a level of knowledge to participate in the CyanogenMod effort. Most CyanogenMod users are not that good.
But if that's where you want to go... start by downloading the Eclipse editor. Then get the Android Software Development Kit and Tools. This in its self is an effort worthy of half a day's work.
Also, remember, Bluetooth comes in many different forms. If you are listening to Stereo Music, you are probably using Bluetooth A2DP. If you are talking to someone, you are probably using Bluetooth HFP. If you are typing on a keyboard, you are probably using Bluetooth HID. I'm betting that your car-ieee-dongle-thing is using a serial port Bluetooth protocol. I think Bluetooth SPP? Which Apple doesn't allow. Or at least did not in the past.
edit: added later...
This looked interesting. Maybe you will find something you can use here:http://antweb.me/index.php/blog-reader/items/installing-a-usb-bluetooth-dongle-on-a-beagleboard-xm-running-android-ics.html