Well, if you still want to use it as a jockey box, run some hot PBW through the coil with your pump, then starsan, then RINSE. Then, do 2 things:
1) Continually run water into the jockey box, as you also drain it from the bottom. Recirc the wort back into the kettle, preferably in a whirlpool configuration. You'll want to drain from a diptube at the bottom, while returning the wort back to the surface at an angle. Check out MrMalty.com for pics.
2) Once you get down to 120F or so, stop draining from the bottom of the cooler, turn off the water going in, then dump a bag of ice in....or use all the ice you have in your fridge's icemaker. You should be able to rapidly cool to 70F.
OR,
You could yank the coil, get some compression fittings, and make yourself an immersion chiller.