It's okay to be concerned. Someday I want to have children, i'm only 23 right now though. But anyways, it is an extremely low chance of passing it on. I would almost say rare. So you shouldn't worry. I'll give you the same advice my doctor told me... Have fun and try to lead a normal life, have children and get married when you are ready. Just because you have m.S. Doesn't mean you have to throw your dreams away.
My grandmother also has ms and she has nearly had it for 30 years which is the age most people live with having ms! Ummm statistics say that there is like a 1 in 50 chance of getting multiple sclerosis if a family member has ms. It scares me and my dad knowing these statistics but there is also a chance that they wont have ms. Im pretty sure that a baby would be great for you!!!
The chances of your child getting ms, if you have it, are something like 8 times higher than for the general population -- but that is still not a huge chance. Not to put a negative spin on it, but there is just as much chance of any baby having some other kind of birth defect.
If you want to improve your child's odds, you should move as close to the equator as you can -- the effect of latitude (probably sunlight) seems to be able to overcome a good proportion of predisposition. Studies show ms is lower in places closer to the equator, and people who move to those places have lower ms rates than in the places they moved from.