I did the same thing with my 2001 CLK.

Go to the parts department at the dealer and find out what assemblies are sold for your model.

In my case I could buy the following:

New bracket arm (includes motor).
New housing (includes the light lens and is factory paonted).

Just figure out what is broken and replace w/ parts from the above assemblies.

I was able to repair everything from the outside of the car.