Johnson Ballast Pump replacement IMPELLER?

[Mouse3]

I buggered the impeller frequently pulling the running pump out to reprime it. Two questions:
1. Has anyone found a place to just get the little impeller?
2. Does anyone know if a "new" 1250 gph cartridge will fit inside a 1000gph body so I can upgrade flow to the sacs?
Thanks in advance for the help.
2010 RZ2 with MLA sac upgrades.