The other end is held in the master cylinder by a rolled steel pin that is pressed in. The pin needs to be pressedd out, and the line removed / replaced and the pin pressed back in.
With as much room as there is to work I think it is nearly impossible to do this in the vehicle. What you will need to do is remove the master cylinder with the line attached, replace the line, then reinstall them together.
To remove the master you need to pry the push rod off the clutch pedal (and no break any of THOSE plastic clips, they are probably brittle, and are very difficult to get) then twist the whole master cylinder counter clockwise about 45 degrees and pull it out, probably with the rubber hose and fluid resivior attached too. Don't break the fluid resivior either I think those are unavailable now too.
Seriously, what were you doing with vice grips? As I'm sure you already know all that did was cost you an extra $100 (so far) and twice as much work.
For future reference, everyone listen! , if you need to get the trans out and can't get the hose off, this is what you do. Hit the frigging slave cylinder port where the hose attaches with a hammer and break it off. Then, once the trans is out of the way, you can use a dremel tool or whatever to get the broken part off the hose without damaging it.
That way all you need to replace is the slave cylinder, which probably should be replaced anyway, and is cheaper than the hose too. Plus with the trans out you have room to work on that end of the hose as opposed to F-ing around pulling the master cylinder out and breaking a bunch more unavailable parts.