If it's only a matter of copying one of the keys that has the four cuts, two on either side of each blade, you might be surprised at what some shops can cut.

Admittedly it won't be in steel like the OEM, but if you want to have a spare just in case something happens while you're waiting for the dealer to cough up the replacement...

In the Tacoma, WA area, Guardian Security can make them, while you wait.
I have purchased one spare for each of my cars, costs $25, if I remember correctly.

I know that won't do much good for you in NJ, but you may well find a solution among the lock shops in your area, especially if you can find a good sized one, rather than the little kiosk in a hardware store!

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-Josh
Testing the cheap Mercedes axiom, one bolt at a time...