Irregular slepping hours....Pls help!?

My daughter is 3 years old and she has irregular slepping hours. She wakes up around 11 am or 1 pm...takes a nap at 8 or 9 pm ...wakes up 2 hours later...slepps at 4am till 11 am or 1pm....still drinks milk every 3 hours even during her slepp sometimes if she doesnt take a nap then her slepp pattern is normal but this is rare. She stays with a maid but her maid will be going back soon. None of the maids have manage to change her slepping pattern...how do i change her slepping pattern or is sending her to a nursery better and can it regulate her slepping time. I work from 8am to 6pm. Im so exhausted with her slepping time and i cant find anyway to make her slepp normally. Shes a happy, bright and healthy child. Has anyone face this problem. Pls advise. Serious answers only. Thanks