Man, that really sucks. Hope you get it all sorted out. The reservoir is basically there to prevent air in the lines. If there's a tiny bit of fluid left in the reservoir, you can still top it off. But if it's gone completely, there will be air in the lines when you add more, and that requires that you bleed the system.
( Click to show/hide )And FYI, if you have the tools (probably not at your GFs place) and the confidence that with time you could do it (seems you do), I would think just about anyone who can follow instructions can push the pedal. If it's likely they've never done anything like this before, you definitely want to demonstrate on another car's brake pedal. I had my wife practice first on her Acura (with it on to make it easier) to get a feel for the speed, and explained that pumping too fast would cause air bubbles and set us back further and take more time. That got her attention since I already told her that her leg would be sore after we were done
Oh and I use ATE Super Blue and ATE 200 (gold) and switch between them when I change brake and/or clutch fluids. It makes it easy to tell when you've cleaned out the old fluid
It can't handle the heat quite as well as Motul, but it's better than stock and does just fine for braking during "spirited driving".