Where in the country are you? If you are close to South Carolina and the car is built, then it would be a good possibility to have the car in 4 weeks.

I would call BMW Customer Service 800-831-1117 and see if they can track the order for you. They have been pretty spot on with delivery times.

I was in a similar situation as you, and my dealer got me a car to drive while I was in between cars. Maybe that could be another option for you.