Here is the story:
The remote key costs about $150 (the wallet key is about $50). Go to the parts department at your dealership with your license and registration, and the will order you a new key. There are only two places in the world that cut BMW keys (Germany and New Jersey). So, your dealership will more than likely send the request to NJ, they will cut the key and overnight it back to your dealership. So about 4-5 days.
Keep in mind, the key does not come programmed!!!! The dealer will claim that he has to do it and charge you an additional $50. You can do it yourself. Here are the instructions:
1. Get in car and close all doors.
2. Put key in ignition and turn to position 1, and then back off and remove key from ignition.
3. Press and hold button 2 (unlock)
4. While holding button 2, press button 1 (lock) three times (in less than 10 secs)
5. Release button 2
6. Door locks wil cycle to show programming has been completed for that key.
7. For other keys, start at step 3, you dont have to put the other keys in the ignition...just push the buttons on the other keys and the door locks will cycle at the completion of each key.
If the doors dont cycle, it didnt work. I did it on my first try, its not hard at all.
Hope this helps