What i always do when i feel a cold coming on or i have a cold is to up my Vitamin C consumption HEAPS, drink a tonne of water, rest (no training, weights, cardio, its hard i know but a few days off won't kill you, lol) and as Dnaielson said, eat heaps. Whenever i have a cold i always get really hungry.
As for medicines, take whatever you feel necessary. Above is kinda like a natural approach to "flushing" the bug out of your system. It always works for me and within a couple of days im good to get back into training.