540i Keyless remote

I just purchased 1994 540i. The key it came with has a built-remote with three bottons. The problem is that all three bottons are gone. Only three holes left. What is the best way to go about getting a replacement key with built-in remote? Any help would be appreciated. Thanks.

Peter

I also just purchased a 1994 540i. I have the same situation with my key. I called JMK BMW in Springfield, NJ. I was told the replacement key would be $145.00. I did not ask how long it would take.