They diss the zinc preparations like Cold-Eze & Zicam, but I know people who swear by that stuff. But if it's mold that's causing your probs, in addition to swabbing down your apt. with clorox & getting that dehumidifier, you might benefit most from an antihistimine.
My friend whose sister is a GP told me to forget about those Cold-Eze and "immune system boosters" because they actually tax the system once the cold has taken hold, but that might only be in my particular situation; they probably work in the earliest stages of aquiring a cold.