How much does to cost to take a nanny to Mexico?

Hubby & I are looking at traveling to Playa Del Carmen with our 6-month-old for 3 or 4 nights. We would like to have a nice vacation with peace of mind, so are looking into bringing a nanny along with us. We live in Seattle. I'm thinking we would pay for flights and accom (we are trying to find a deal that includes meals too). How much would we then need to pay per hour? How many hours a day would be reasonable for this vacation nanny to work?