Was he sitting just past the top of the bridge? The Toronto Police always set up on the Adelaide Bridge, usually just east of the DVP where the ramp splits off. They also run a trap on Richmond Street just west of Parliament - catching drivers coming off the DVP into downtown. But that's beside the point.
Anyway... couple of things to get started... send the ticket in with the not guilty/trial option checked off. File a disclosure request, so you can get the officer's notes. Also ask for a copy of the radar (or laser, if that was used) manual, proof of the officer's training and calibration of the device. At a minimum, you must get the notes and access to the manual for the Crown to have satisfied the disclosure obligations. If they don't give you the manual after making a couple of attempts at disclosure, you can file to have the charge stayed. If they can't give you a trial within 10 months or so, you can file to get the charge stayed based on unreasonable delay.
You can also try plea-bargaining; depending on your insurance provider, they MIGHT be one that forgives a ticket for 15-over or something like that... but check it out first. (Be careful about calling them, some have used calls asking about tickets to raise rates.) You could try seeking an on-line quote, anonymously, just to find out.
At the very least, starting to do the ground work for fighting the ticket will buy you some time.
BTW - do you know if the officer used radar or laser?