Your passport and ticket MUST show the same name and you cannot change the name on your passport without a legal document saying why it is acceptable, usually your marriage licence. However you do not get your marriage licence until you are married.
Therefore the simplest thing is to book your tickets in your maiden name and travel on that name. You can then leave your passport as it is until it is next time to change it, remembering to book tickets in your maiden name, or pay the money and have your passport changed once you get home.