N.V.
It's been my experience that the more I go into our daughter (to give her her binky, etc.), the more she would have sleep issues and I'd have to go in more often. We also have a 2 year old son, and I was so scared that his sleep would be interrupted; however, when I finally let our baby girl 'cry it out', our son slept right through (and never wakes up when she cries at night), and our daughter finally learned to sleep on her own.
It might be best in the long run for you to let her learn how to sleep on her own, and you may be surprised to find that your 2 year old is a sounder sleeper than you might think!
Best Wishes!