Well, if you've got a virus (like a cold), antibiotics aren't going to help anyways.
At this point, you're going to want to boost your immune system as much as possible while minimizing symptoms.
Vitamin C doesn't really boost your immune system while you're sick, because it restricts viral access. However it will help stop new viruses from taking advantage of your weakened state.
Vitamin E increases your "killer cells", which seeks out and eliminates cancer cells, bacteria and germs. Again, not as useful when you're already sick, but it will help contain the problem.
Beta Carotene helps boost T-cells and killer cells.
Garlic boosts production of white cells.
Essentially, you're going to want to eat as healthy as possible and curtail any unhealthy habits. Now would be a good time for fruit smoothies, multivitamins, garlic mashed potatoes (I always make thes when I'm sick), and to gargle with salt-water. If you're a manly man, and I mean if the very mention of your name strips women of their clothes and puts hair on the chests of boys, then you can try gargling apple cider vinnegar as well.