How old is your daughter now? I know that age does matter for your daughter's custody based on shariah law. Also I advise you to read the below information, it may help you understand some laws regarding child custody. Wish you good luck!

http://www.expertlaw.com/library/family_law/islamic_custody-3.html#81

Read:
-Child custody following divorce
-Requirements of a mother custodian
-A mother's right to physical custody