How many days do you have until you leave? If you have a couple more, getting some antibiotics might help speed things up.

Pseudoephedrine is the best decongestant ever. Some Sudafed types have it (it'll be listed on the active ingredient list and probably the front of the box). I know Walgreens has their own off brand with it too. It's a semi-controlled substance in most states. They keep it behind the counter in Texas. But it works the best out of everything I've tried. The last time I had a really bad sinus infection I was told to take it by my doctor over things like Dayquil, which did hardly anything.