As a US citizen, you can petition the US government for your daughter's immigration. You do that from anywhere in the world by filing an I-130 petition with the USCIS. It costs $420 and takes about 5 months to be processed.
http://www.uscis.gov/portal/site/uscis/menuitem.5af9bb95919f35e66f614176543f6d1a/?vgnextoid=c67c7f9ded54d010VgnVCM10000048f3d6a1RCRD&vgnextchannel=db029c7755cb9010VgnVCM10000045f3d6a1RCRD
Thereafter the petition goes to the National Visa Center (NVC) in New Hampshire and they will contact you for the mandatory Affidavit of Support.
Since the US government needs to make sure that no foreigner becomes a public charge, every intending immigrant needs a sponsor. The form for this is I-864 and you'll need to make at least $18,912 after taxes, assuming you have no dependents, such as children, to qualify.
http://www.uscis.gov/files/form/i-864p.pdf
What they want to see is your latest US income tax return. If your income is not sufficient, you will need either a co-sponsor, or you can make up for it with assets at the rate of 1:3.
After that's been taken care of, the entire package goes to the US consulate in Ciudad Juarez, and they will ask for paperwork, a medical, police reports, and schedule an interview. If that goes well, your daughter will receive her immigrant visa and has thereafter up to 6 months to "activate" it. The moment she arrives at the U.S. border and is processed and formally "admitted" for immigration, she is a Green Card holder. She then needs to live "under your custody" which is the case when she wakes up the next morning in your house. About 2 weeks later her Green Card will arrive in the mail, and that's when you two go to the nearest U.S. passport office and apply for a US passport book and (as a backup) a US passport card for her. Only thereafter she can travel back to her mom as every US citizen is required to exit and to enter the United States with a US passport.
Now here's the problem with your particular case. In order for the US consulate to issue her an immigrant visa, you will need to produce the mother's consent that her daughter immigrates to the United States and lives with you. There is no way to make a special contract that you will send her back the moment she has become a US citizen. So your main deal will be to convince your ex wife that you just "need" your daughter for 2-1/2 to 3-1/2 weeks (if you go to a passport agency) or 5 to 6 weeks if you apply for the passports at a regular passport office. If mom doesn't trust your word and refuses to sign on the dotted line, you have a problem.