Hi Erika!
Your family will have so much fun visiting Walt Disney World Resort! I'm directing you to the Walt Disney World
ticket page so you can try different scenarios of tickets and pricing. Disney offers great incentives to purchase multi day tickets. The more you play, the less you pay. Because your trip is fast approaching, I'd suggest purchasing your tickets at the front of the Theme Park. Typically, ticket processing, shipping and handling can take 14-days if ordered from the website.
Basically stated, you have options of either "Base Tickets," "Park Hoppers," or a "Water Park Fun & More" option. Your baby will not need a ticket to any of the Parks. Base tickets will allow you to visit one Park per day, whereas the Park Hopper will allow you to visit multiple Parks per day. In addition to admission to the Theme Parks, the Water Park Fun & More ticket option allows you a specific number of entries to the miniature golf courses, Disney's Oak Trail Golf Course, DisneyQuest, Disney Water Parks and ESPN complex.
I typically recommend first time visitors purchase "Base Tickets." There will be so much to see and do in each of the 4 Disney Theme Parks, you will not need to upgrade your ticket price to "hop" around.
How many days do you intend to visit, Erika? I'd be happy to recommend an itinerary for your family.
If you'd like to speak to a friendly Cast Member about your options, simply call 407-939-5277. If you'd prefer to send an email, you can contact them at ticket.inquiries@disneyworld.com.
Wishing you a magical trip!
Sherri