I went to radio shack and bought a 2 foot apple cable for like $10.00.
Edit* even better from amazon
The one I got is a purple 3rd party cable (Gigaware), because f spending more money for the same thing.
The cable is not your problem. Any iPhone cable will work. The loss of functionality is usually caused by your "tethering" setup. For example, if you have the AT&T grandfathered unlimited data plan, you can never use these features as tethering is not allowed.
If you have a regular data plan, you need to turn on tethering before the head unit can access your internet connection.