while you can perform by-pass surgery with a rubber hose, I wouldn't recommend it. The main reason being the system that is being worked on. Brakes are something you don't monkey around with (at least i won't recommend) Remember I paid almost $500 to get the brakes on Billo looked at professionally after doing everything else myself. You are lucky to have discovered the leak driving the car at low speed. You may not get a second chance. The brake fluid works under high pressure when the pedal is pressed and even the cheap flexible brake lines balloon up when brakes are applied. This results in a loss of braking power. The metal brake line may be corroded at other spots and it may rupture at another spot this once.
My humble suggestion. Don't worry about the aesthetics. Get a local mechanic to run a new copper brake line front to back and bleed the system. the line should be run along the same route as the original but does not have to enter the tunnel. It would be a temporary measure (but a safe alternative) till you can run the proper lines.
Rubber / PU hose with clamps...NO!
