RECOMMENDATION NEEDED: 3D/4D ultra sound?

Does anyone know where I can get a 3D/4D ultra sound in the Sterling Heights/Troy area?

I have family in the area that wants to take me for one (we live out of state) and can't find any place that will be open on a weekend to provide the service?

There are store fronts (not a part of a doctor's office) all over the place where we are that offer these services, and in MI they seem few and far between? All the doctor's offices I have called require you to be a patient IF they even have a 4D machine.

 Help!