General Maintenance & Repairs - HELP! Brake Leak! Bad!

Okay. So yesterday I went up to Daves Muffler in Durand, MI to get my SLP loudmouth.
I went and picked up it up and drove it home.
While in my driveway I realized my brake pedal was feeling weird.
I could push the pedal all the way to the floor and I could barley stop.
Today I filled the reservoir with brake fluid and it fixed the problem...
For about 10 minutes.
I pull my firebird out of the garage and the brake pedal has no pressure again!
I get under the car and look.
It is leaking from the rear driver side brake line pretty bad.
Here is a video of what it looks like

http://www.youtube.com/watch?v=Ch2JXL1dnq0&feature=plcp

When you see it pouring out is when the brake pedal is applied.
I have never had this problem before.
Do you think the guys hit the brake line with the torch?
What do I do?

Anyone?
I need to drive 80 miles Friday

I'm gonna go out on a limb and say since I see you are from MI that the line rusted through after all these years, but it could have happened at the muffler shop. Only way would be to crawl under and look to see if it looks like it has fresh marks or a burnt spot from the torch on it

^^^^ Like he said, get under there and take a look at the damage.

I'm going to take a guess and say it was done at the muffler shop.

My Brother's Girlfriend's Dad (lol) is a mechanic.
He came over and took a look at it for me.
He said it is possible they hit it with the torch but the lines are rusted pretty bad and should be replaced anyway.
He quoted me $150 - $200 for lines and install.