Steering problem
2000 Volvo S80 6 cyl Front Wheel Drive Automatic 118000 miles

The adjustment lock for the steering wheel has broken and now I can move the steering wheel up or down, in and out all of the time. Needless to say, it isn't the safest way to drive the car. It would appear upon closer inspection that the lever that locks the wheel in place has a plastic clamp that has broken.
Two questions:
1. What is the name of that part so that I can buy one?
and
2. How do I fix it?

Thanks in advance,
Mike