Broken pulley on alternator

[Tomass]

Hi,

I need an advice on what to do next with my alternator.

Option 1 - Buy a new alternator
Option 2 - Remove the broken pulley leftovers (no idea how)
Option 3 - Fix the alternator by replacing the center (shaft?)

Basically, the pulley broke and I believe some leftovers are still on the alternator. Not sure if I'm able to remove them. The alternator was working fine so I believe that there is no need to pay £150 for a new one, unless there are no other options. It also has a few bad scratches because of the broken pulley.

I've attached the pictures... Thank you