Jack it up and support the car on jack stands at the frame rail, get the brakes and backing plate out of the way, make sure the car is high enough that the lower control arm involved can swing down 90* from the car. Loosen the strut rod nut at the K memeber end and the lower control arm pivot nut. Jack the car up by the lower control arm in question to the point that all the weight is on the floor jack but just barely off your jack stand. Take the spindle loose at the upper control arm and pivto it out of the way, knock the lower ball joint and outer tie rod loose and remove the spindle. Lower the floor jack and allow the lower control arm to swing in as much as the tension will take it. Be aware that I have had them kick the jack at the end of the stroke so make sure you are in a safe position where no flesh or apint will be injured. Once it is hanging vertically it will usually be loose enough you can remove the clip and push the control arm backwards which push the torsion bar out and free so you can pull it out of the arm socket. As far as the broken bolt replace the arm. Easiest way.

Good luck and be careful.