Need Help!

A part broke in my interior today, I was hoping somebody could tell me what it is so I know what to look for in a parts catalog. I'll try to describe it:
Its under the steering wheel column, there are 2 knobs, and one of them broke off.. I have no idea what they do or what their called. If anyone could help me I'd REALLY appreciate it... BTW its a 1971 Stingray 350/auto.

On my '70 there are three knobs under the steering column. There is a bigger round one in the center with a stalk type on either side.

The middle one is an electric cut-off for the windsheild wipers - turning it lets you stop the wipers and not have them fold away.

The one on the right allows you to manually raise or lower the wiper door without turning on the wipers - pull it down to open the door, push it up to close it.

And the one on the left allows you to pop up the headlights without turning on the lights - pull it down to raise the lights, push it up to lower them.

All three are labeled in the picture of the dashboard at the beginning of the Instruments and Controls of the owners manual. The wiper controls are discussed in the Windshield Wiper and Washer section and the headlight switch is discussed in the Headlamp Operation section.

There is a 4th knob under the dash of to the left of the steering column. That one resets the trip odometer.