echinacea! Get the liquid. Put it under your tongue-be warned, it tastes pretty bad. BUT...
the first time I ever tried it, I was getting a miserable cold-sore scratchy throat, watery runny nose, watery eyes, fever, the whole thing. I ended up taking like half a bottle (a small 4 oz bottle) of echinacea over about 8 hours. Went to sleep, woke up the next day feeling perfectly fine.
You could try loading up on vitamin if you can't get echinacea- a lot of the docs my Mom worked with would OD on it when they felt a cold coming on (like 5k milligrams or whatever-5 times the RDA). It would give them diarrhea but the next day the cold was gone. Apparently zinc is very helpful there as well.
Good luck!