Hello and welcome to Just answer.com, Super mechanic here. About your vehicle.
Yes the pulley has to come off first. There is a tool for that, (as well as putting it back on) that you can normally borrow from Autozone. Here is the procedure.
POWER STEERING PUMP REPLACEMENT
REMOVE OR DISCONNECT
INSTALL OR CONNECT
NOTICE: Do not use arbor press or Internal damage to the pump will result.