I2C RTC AT24C32 DS1307 Real Time Clock Module http://www.ebay.com/itm/121014967852?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
this device does not come with the ds18b20 (some may but not this particular one) so theres an empty spot for a to-92. i dont have a ds18b20 but did have an LM-34 lying around. This will work with any to-92 where the center leg is Vout, you just might have to flip it around to marry up vcc and ground.
R1 is a 3.3k pullup resistor for the onewire bus, remove it, install your new sensor.
on P1 sq is 1307 sqare wave, ds is your temperature sensor, and bat pin goes to analog input to monitor rtc battery. P2 is just to chain other devices if you want to.