For anyone in the US with select 450's the MB Companion app is a great way to send addresses to your car, check your tire Pressure, and even see how much fuel you have left. However, for those outside the US, the app is simply non existent. Luckily for you we have a way to for you to get it.
The first thing you will need to do is create a US Apple ID. You can do this by following the instructions here.
After logging in with your new Apple ID simply follow the link to the MB Companion App and "purchase" the app.
Now all you have to do is follow the onscreen instructions in the app to link your car and you are on your way.
*Note you will probably want to sign out and sign back in to your main iTunes account after you install the app. When Mercedes pushes an update, it will prompt you for the PW of the US Apple ID.