Bluetooth for a 03 SL 350

[03D64120]

I have a 03 SL 350 which has a factory fitted docking station for a Nokia 6310i.
I now have an iPhone 4S. How do I achieve hands free? Is there a bluetooth kit that can be easily retro-fitted.

 

[npuk]

http://www.mercupgrades.com/Choosing+Bluetooth+Cradle+for+European+Mercedes+Vehicles-article-41.html