you can take your car seat on board as long as it is within their size limit. Check on their website as details are given there. If you have not booked an extra seat for your baby then the car seat can go in the hold and the baby will sit on your lap and be given a lap belt which attaches to your belt to secure the baby to your lap.
The buggy can be taken through the airport up until the steps of the air craft then someone will load it into the hold for you and take it back off again at the other end.