It appears that you can claim her as a dependent. You will need a Social Security Number (SSN) or an Adoption Taxpayer Identification Number (ATIN) for her. The IRS Instructions for Form 1040 say the following.
"Adopted child. An adopted child is always treated as your own child. An adopted child includes a child lawfully placed with you for legal adoption."
"Adoption taxpayer identification numbers (ATINs). If you have a dependent who was placed with you for legal adoption and you don't know the dependent's SSN, you must get an ATIN for the dependent from the IRS. See Form W-7A for details. If the dependent isn't a U.S. citizen or resident alien, apply for an ITIN instead using Form W-7."
