You sure it's the frame mount? As in, the metalwork of the body is now cracked - not the shock mount itself?
The longer you wait to fix it and continue to drive on it, the more the upper suspension link will knock around in there, which will probably make it harder to repair.
I've heard repair quotes for that from $200-300. It should be taken care of. It's not going to kill you, but it's certainly not good for your car.
From your signature pic, your lights need to be adjusted as well. Specifically the passenger side. There are some DIYs online, or you can take it in for about $20.
1993 325is - Frigg - Grounded
2001 Z3 2.5 - Išunn - Active