Just ordered one and it arrived in a day and a half. It came from the following:

Mercedes-Benz USA LLC 15050 Frye Road Forth Worth, TX 76155

You wil need to provide VIN, something to prove you own the car, registration, etc., and a photo ID.

Cost: 150 including tax.

Hope and pray you are not one of the cars that Chrysler lost the key code setting for. If you are well it requires major work.