Heh, many questions but important ones!
Actually, nuking the tank might be a good idea.
By nuking I mean killing off all living things that may be living in it (not the fish or plants tho
LOL). Best way to do this is to move the surviving fish into another temporary tank, pull out everything and rinse it in a 9 to 1 water to bleach ratio. Even dip the plants in it (watch the roots), Throw away the filter media. Rinse all the tubes, and wipe down any cords that actually into the tank (like the heater cord). Soak the gravel in the bleach mixture, and either wipe the tank down or soak that as well. Don't do this until you get the antibiotics, then when you return everything treat the fish
ASAP so they don't reinfect the tank.
As for what to do now, well, not much you can do. Just as when we get a bad bacterial infection that we can't kick ourselves, we need those antibiotics to help rid ourselves of the infection, so it is with the fish. You may want to reduce the temps a bit; that MAY slow down the infection as bacteria lurve warm moist places, and don't multiply as rapidly is lower temps (say, 72-74F rather then close to 80F).
*slaps self in head* I just checked, and realise I never gave you this link; there may be more info that can help in here:
http://www.aquamaniacs.net/flex.html