I personally have not heard any doctor say you need to keep a newborn indoors for 6 weeks after they are born. I have read and been told that as long as your newborn is healthy, there is no reason you can't take them anywhere as soon as you are up to it! In fact, keeping an infant away from germs can hurt their immune system...being exposed to germs and allergens is the only way for a body to build up a resistance to them. If you are planning on breastfeeding, your baby will get an immunity boost from your colostrum in the first week after she is born.
Both my children were taken to relatives' houses, friends' houses, restaurants, stores, etc. all in the first week after being born. Neither of them got sick within the first few months of life, and they are now very healthy little kids =)
The only advice I would have for a baby born during the winter, is that infants need 1-2 MORE layers of clothing than what you have on (if you have a long-sleeve shirt and coat, your baby should have a tshirt, long sleeve sleeper, coat, and blanket...just an example...)
I would certainly make sure that no one you go visit is currently sick...but the fact is that with most colds, you are most contagious BEFORE you show any signs of being sick...so you wouldn't know anyway =)
So I wouldn't worry about it too much, so long as she is healthy, she will be just fine!