01 Sierra Brake Line Problem

[simmonsp5]

i have an 01 sierra and today when i put on the brakes and the pedal held then went to the floor when i got home i noticed i had brake fluid all over the rear window and pouring onto the ground. i had someone press the pedal in and i can see fluid squirting out between the cab and the bed of my truck on top of the frame. any suggestions on what i need to do to get this fixed looks to be a hard place to get to