After you gargle the colloidal silver, are you swallowing it? While you have this infection, besides putting colloidal silver drops in your ears, and you should do this several times a day, when you gargle (also several times a day), if you are not swallowing the colloidal silver, then swallow. Besides that, to make sure the infection is erradicated, I would take at least two ounces daily of colloidal silver internally. You may want to include probotics to insure that the beneficial bacteria in your intestines remain thriving.
After you are well, you may want to stay on a preventative dosage of colloidal silver, say one tablespoon a day. This will prevent the infection from returning.