The puller you want is a Pitman puller. In Canada, I've seen two types: fixed jaw and adjustable jaw (more expensive). This was at a "Princess Auto" store. Most automotive stores sell them though. However, you should find that a two leg gear puller will work. Some pullers are only supplied with a pointed nose. If so, use a nut over the point to keep the nose on the ball stud.
A word of warning: use the puller CAREFULLY when separating the arm/ball joint. Increase the pressure SLOWLY ( half turn, pause, half turn, pause ) the joint can separate suddenly and too much pressure will cause puller and joint to fly about once separation occurs. Leave the ball joint nut on, but backed off a bit to stop the joint and arm separating explosively. Watch your hands and eyes, play safe, wear gloves and safety glasses.
Have fun !
Teaman3