Without repeating some of the ideas already mentioned, garlic is a proven natural antibiotic. Ideally chop the cloves, then mash them fully crushed, wait about 10 minutes for the allicin to form and swallow. It's best in the morning before breakfast. You can add a touch of honey to help it go down.
And one other thing about the prescription antibiotics ... don't overlook the detailed warning that says take with a glass of water and avoid laying down for some period of time, ideally an hour. You want them down into your stomach good, else some of them can really burn up your esophagus.
Yeah, we're big fans of garlic around here also. We have some big garlic-stuff olives that are just fantastic.
Funny you should mention that warning. I read it last week (it said don't lay down for at least 30 minutes) and use a full glass of water (along with some food), and I wasn't sure why. Seemed quite odd to me. I'm glad I'm done taking them.