I'd have a close look at the damaged area as it might not extend into the pumping area.

There is a pump wear fix it plate but I haven't used one and am not sure if they need glued in or not. https://www.wittrans.com/parts.php?&type=722.6&group=HARDPARTS&notPictured=1&categoryNumber=2010&category=PUMP%20COMPONENTS

A78544E
Price: $30.07
Core Charge: $0.00
Available: 3
PUMP WEAR PLATE, 722.6/722.9

Also look here for info. http://www.atraonline.com/gears/2005/2005-09/2005-09_26.pdf
You will also need to get creative with your snap press by using various pieces of large dia exhaust pipe / bearing races. There is an L shaped snap ring that needs the spring compressed fully before it will come out.