Clutch Pedal stays on the Floor

2004 Chevrolet Cavalier the very Basic Model don't know exactly the Model, because everything is Manual on the Car-I never got any kind of symptoms and I was driving home and all of a sudden my Clutch Pedal stayed on the floor and no pressure, I had to towed my car from 4 blocks away to my house. I never had any leak sign in my garage floor but now I do when I try to press or push up and down the clutch pedal. I was told that maybe a Clutch Master Cylinder or Clutch Slave Cylinder is bad. I went to the dealer and asked question on how and where to find both of the parts and I was able to find ONLY the Clutch Master Cylinder but not the Clutch Slave Cylinder Only because I was told that it's inside the Transmission and that it will need the Transmission to be remove to replace the Clutch Slave Cylinder is this true? I was also told to check where the fluid leak is coming from and I check the Clutch Master Cylinder and around for any kind of leak and it was all dry, Can the Clutch Master Cylinder go bad even though the outside and around it are all dry? Could this be my problem that my Clutch Pedal stays on the floor? There is however, a fluid leak underneath the engine right between the engine and the Transmission. Or will this Clutch Slave Cylinder be my problem? But before this day I never had any kind or sign of leak and I park my car inside the garage. Any advice is appreciated, thank you - nice site :-)