S.K.
T.,
You need to double check on bringing your daughter on the flight. The "free under 2" rule is a U.S. rule. When we looked into flying to Mexico, we found out that we would be charged to have her sit on our laps. We also had to put her on the flight itinerary, we couldn't just show up with her even though she wasn't getting a seat.
Make sure you aren't booked in an exit row seat. I also learned from a flight attendant a few years ago that there is an extra oxygen mask on the rows on the right side of the plane, so that's where they want the lap children.
You can check carseats as luggage for free in the U.S., even if you don't buy a seat for your daughter. You will have to call the airlines for the international flight policy.
Also, you need to make sure immunizations are up to date. I read that everyone needed a Hep A four weeks before leaving. Also check the WHO (world health organization) website for the latest policy on yellow fever vaccinations and the current malaria situation. Risk for Malaria is low, but it depends on where you will be.
Good luck,
S.