The port pin cannot drive the relay, either. The port pin is only capable of sourcing ~25mA@ 3V; you will have trouble finding a relay that sensitive. You will need a grounded emitter NPN transistor, whose base is driven from the port pin through a current-limiting resistor; and whose collector drives one end of the relay, and where the other end of the relay is connected to 12V (not 5V). Depending on how much current the motor draws, you can probably just use the transistor to drive the motor.
The LM35 puts out 10mV per degree. If you use 5V to power the PIC, and if you set up the PIC's A/D so as it uses the 5V as its reference, the 10 bit A/D will quantize the range from 0 to 5V into 1024 steps, or ~5mV per step. That will allow temperature to be measured in ~ 1/2 degree steps. If that is good enough, then you can dispense with the opamp. If you set the opamp up with a gain of 10, then that will give you 20 A/D steps per degree.