You can give Maracyn 2 a shot, but I'd say your chances of saving her are exponentially greater with colloidal. M2 is much less expensive and available at most LFS.
It's totally up to you, though.
You'll want to get her into that hospital tank as soon as you can, though.
I'd just take some tank water out and toss it into the 1 gallon bowl so at least the temps are right for her.
I would stay away from tossing any salt into the hospital tank, too, cuz that will only help hold the fluids in her and you don't need her any more puffed up.
good luck!!!