Good for you! Realizing what your passions are will make you more successful. So kudos on that.
Umm...and I don't know how to answer your questions and not take up the whole post. There are SO many things you can do to get your name out there and bring clients to you. One of the main things is that you have to realize that you need to bring clients to you - they usually don't walk in on their own accord. Especially if you are new or changing from another area - like weddings. Create concrete goals and track everything. That will tell you what is working and what isn't.
Take some marketing classes (doesn't have to be mine

), read books - especially those on sales and closing sales. Purchasing children's portraits is a very emotional purchase. We've gotten our family sessions to gross over $1,000 per session. I'm bumping the $2K line now. The sales aspect is VERY important.
YOU CAN DO IT!!! Hooray for you!
My daughter is singing at school in about 10 mins. If you have any questions, feel free to PM me.