Hi Saylor,
As you've figured out, antibiotics aren't very effective for sinus infections. Google "CNN sinus infections" to see the study.
What happen is the infected mucus becomes encapsulated, and the antibiotics, which travel by bloodstream, can't penetrate the capsule. The cure for that is to wash out the infected mucus with saline.
I'd start with a Neilmed Sinus Rinse, available at any chain drugstore. If that doesn't work, it means your infection is lodged in the upper sinuses, where the Neilmed won't reach because of gravity. However, this technique uses gravity, rather than fight it
http://www.medhelp.org/user_journals/show/2322
The Flip-Turn Sinus Flush is mildly risky, because you have to bend over to do it, preferably in a shower, but you can also do it outside on soft ground, or you can kneel down and lean over a bathtub, or perhaps a plastic basin or tub, with the shower running for steam.
It may take a few flushes to open up the passages to the upper sinuses, if they are swollen shut by the infection.
Good luck.