I am doing very much the same!
Here is my current working (but not very tidy) setup!
Soldered the wires onto the GPIO pins on top of the OLED display. Then off to a solid state relay to control the 1kW load ( http://amzn.to/2grrQSh )
I'm then using the easy to access jumpers on the temperature sensor to feed 3volts into the solid state relay via the relay expansion which is behind the oled display.