88 260e (w124) need help on brakes

[kevindavis10]

I recently tried to replace the brake pads on my 88 260e, because of the extream wear on the pads the caliper pistons were extended all the way and when i tried to push it back in the piston hyperextened and came out and i lost some brake fluid. I got th piston back in and nothing seems to be leaking but there is air in there. What do I do, local ripoff mechanic says I need new calipers, when i asked about caliper repair kit he said I would have to heat the piston, freeze the seal to get it on, and it was just easier to get new caliper. Please give me advice I usally can fix anything but hydrolics are new to me. Also money is a consideration if i had it i would have let the mechanic rip me off, please tell me the cheapest way to fix