Ok..let'* clarify, your pulley broke.
To get to the pulley to the right and slightly below the water pump, yes, you must remove the motor mount. This mount is known as the torque axis mount.
in order to get the mount off, you will need to remove the power steering pump. there are two 13mm bolts that hold it in place. They are gotten by turning the power steering pump pulley so that one of the holes is at 12 o'clock..the bolt is behind the pulley by putting the socket into the hole in the pulley you can remove it. The other bolt is at 6 o'clock.
Jack the passenger front of the car and support, remove the tire and plastic splash shield to gain access to the motor. One nut/stud is visible from this angle. The other two can be taken out from the top.
00 Regal GS: All kinds of cool stuff.