Datalogger Temperature Sensor

I would like to use my AXE110 Datalogger to record temperatures. I have tried the DS18B20 digital temp sensor that is supplied with the datalogger, but it seems to give readings in 1 degree C units. I would like a more sensitive response, something like plus or minus point one degree C, or better if possible. I am not interested in the actual temperature, only the rate of change of temperature. Any ideas anyone?