Here is a link to the process for adjusting your status based on your marriage to a US citizen
http://www.uscis.gov/portal/site/usc...0045f3d6a1RCRD
You can make an appointment with your local ICE office and speak to them about your situation. Here is the link to the appointment system. There should be an office near where you are.
http://infopass.uscis.gov/
If you marry, and procede with adjusting your status to a permanent resident, you would not need a waiver. The process will allow you to file for work authorization.
Whether the organization will allow you to continue to work as and AU PAIR if you do adjust your status based on Marriage, you need to ask them.

