You will need to "back" bleed the brakes,,from the bottom up. I have read of fashioning a pressure bleeder with rubber tubing and a large syringe. Push the fluid from the caliper up to the master cylinder.
(I performed a quick forum search on "bleeding brakes" and noted the detailed version of the above)
Take the cover off your master cylinder. Check the level of luid. If it is at the max then you will have to remove some. This method works a treat. Get a syringe, from a vet supllys or pharamcy. Fill the syringe with fresh brake fluid, flick the syringe to remove any air bubbles, attach the syringe to the bleed nipple on the caliper using a length of clean plastic tubing. Crack open the bleed nipple whilst forcing the brake fluid through from the syringe, keep an eye on the level of fluid in the master cylinder, make sure you put enough fluid through to clear out all of the old fluid and air bubbles by using a syringe with a capacity larger than that of your brake system.