Tylenol is paracetamol, which you can take while pregnant. Robitussin is a cough medicine. The active ingredient is dextromethorphan, so I would just look for it under than name, or ask the chemist for something with that in it.
I never wanted to take any medicine while pregnant, though. These always helped me: http://www.food.com/recipe/dr-pats-hot-toddy-cold-remedy-234344
. Instead of the whiskey, use apple cider vinegar.
If you're congested, take a warm shower, or just go into your bathroom and turn the shower on really hot so it steams up the room and sit in the bathroom for awhile.
Other than that, lots of rest and fluids.