For many, an interlock is not required for a first time DUI conviction. A second conviction, however, carries with it a six month time period.
You will need to have an interlock on the car you are driving for the time period imposed by the court -- the interlock will not follow the car.
Best of luck.
In no way am I offering you legal advice, and in no way has my comment created an attorney-client relationship. You are not to rely upon my note above in any way, but insted need to sit down with counsel and share all relevant facts before receiving fully-informed legal advice. If you want to be completely sure of your rights, you must sit down with an experienced criminal defense attorney to be fully aware of your rights.