MOEN Cartridge stuck, Any tricks ?

I wrote an earlier mssg about having an older MOEN single handle kitchen faucet that leaks around the cartridge top and the water comes out of the housing. I tried to pull the cartridge out but only the center comes out the outer part of the cartridge is stuck in the housing part of the faucet. Are there any tricks to getting the outer part of the cartridge out so I can replace it ? If it does come out do they sell replacement O-rings for these ?