Hello and thank you for using our service. My name isXXXXX and I am a licensed attorney and will try my best to help you. I just ask for two things: 1) Before you sign off, please remember to rate me positively as that is the only way that I am paid and your question does not close after you rate me so I can still answer additional questions without additional charge if you have follow-ups even weeks or months later; and, 2) IF I have bad news for you, please remember I am only the messenger. When you rate me, it is my service to you that you rate, not whether the news is good or bad. I will try my best to give you a solution, but sometimes the law does not have a good one.
For her, she needs to file the following forms: I-130 (Petition for family member), I-485
(application for Lawful Permanent Residency), I-765 (Application for work permit), G-325a (Biographic data - one for each of them), I-693 (Medical exam that a certified doctor must fill), and I-864 (Affidavit of support).
You will need to file each form with supporting evidence and appropriate filing fees. You can find these forms at www.uscis.gov/forms
The supporting evidence that you would file would be birth certificates, marriage certificate, divorce certificates if either of them have been married previously, proof of the spouse's U.S. Citizenship, proof of her legal entry into the U.S., and financial documents of her spouse to prove income over the last year at least.
In about 3 to 5 months after filing, she should get a work permit. About 5 to 7 months after filing they should get a marriage interview. If all goes well, a few weeks later she should get a Residency status (green card).
As far as the children, the can file an I-130 for each of them because the Priority Dates are current, but that could change any month. It may be better for the step-father to file an I-130 for each and that would process as if they were children of a U.S. Citizen. Here is a link to the process:
Unfortunately, it will take about a year for them to immigrate unless they have some extreme emergency. Here is a link:
Please let me know if you have additional questions and please do not forget to rate my service to you (not the state of the law) as that is the only way that I can get credit for my assistance to you. Even after you rate the service, I can still answer additional questions for you without additional charge. If you do rate me positively, a bonus is always appreciated. If you would like to request me in the future, just go to http://www.justanswer.com/law/expert-guillermosenmartin/. Thank you!