how can i fix my GE side by side refridge model # GSH22KGRBWW?

GE Fridge/freezer side by side not cold enough/not freezing?
GE Fridge/Refridge cool but not cold enough, freezer cool but not freezing. I hear it kick in and motor running but even with the temp turned all the way up its not working properly. What could be wrong? If its the thermostat how much $ do those range?