Brake Fluid Leak problems of the 1996 Chevrolet 1500

I was driving on highway and was getting off at a exit ramp and I pressed on the brake pad the pedal went to the floor and I did not have brakes at that point and almost hit the vehicle in front of me I finaly came to a stop and checked to see what the problem was and seen brake fluid everywhere under the wheel well I carefully drove it home taking back roads and going very slow got home after a long scary drive and jacked the truck up replaced the wheel cylinder and was going to bleed the brakes but there was no fluid coming from the brake line noticed the brake fluid dripping off of the frame I looked at the brake line and it was rusted and pitted and seen the brake fluid coming from little holes in the rusted brake line. Looked on the internet for ways to replace the brake line and there were so many people with the same problem so I called gm and they told me they could not help me so I went to the auto parts store and I got some steel tubing and started to repair the brake line my self so far I have bent and cut and double flared the new brake line but it started to rain and I have to work so I will finish it this coming weekend hopefully this will work. Could not afford the dealership charges it would cost to tow it to dealership they would charge me to tell me what is the problem witch is very plain to see then add a percentage to parts and then the labor and who knows how long it would take and they charge by the hour so they would not be in any hurry to fix it. I bought this truck brand new and take very good care of it washing and waxing and maintenance there is no rust on the body of the truck and the exhaust is not rusted but the brake line is.