[legion]

A lot of this comes down to the coverage you have.

If you just have liability on your car (and I doubt it on a newish BMW), you will need to work through the truck's carrier.

If you have full coverage (liability + collision + comp) and your wife was not at fault, then I would file a claim with your insurance and let them handle it for you. It will reduce your headaches significantly and it is what that "other" coverage is for. Your insurer will cut you a check (minus your deductible) and go after the other carrier. When they recoup the money, they will reimburse you for the deductible.

Within your coverage, some carriers offer "gap" coverage. This has been covered above. Some also offer replacement of your vehicle with a brand-spanking new one if it is relatively new (like within 1 or 2 years old). Find out if you have these coverages, as they can make this experience much easier for you. Technically, you are supposed to request these coverages, but many agents will include them in all of their policies.