This mutiplex motor is a good fit for the Cessna:
http://www2.towerhobbies.com/cgi-bin...?&I=LXEXU1&P=0

I had bent shaft so i needed replacement. I got mutiplex because I had good luck with this brand in the easystar plane i have. Just be sure you get similar weight as the stock motor so you don't mess up the CG.