You will need to remove the old receptacle by cutting the wire (while the refrigerator is unplugged) and splicing on a new receptacle. You can get new ones in the hardware section. Wrappy exposed wires with electricians tape to prevent a short.
Usually the electric receptacle on a refrigerator is on the back of it. But with my experience it will be a lot easier if you just call a repair man to come and fix it for you.