If I am a citizen of United States and I want to bring my mom who lives in the Dominican Republic, how do I do that?

You can petition for your mother and that process will take about 9-12 months. You can petition for your brother but it will take about 10-12 years for a brother of a US citizen. For your stepfather, you cannot petition for him if he and your mother did not legally marry before you turned 18.

To bring your mother to the United States, you will need to submit an I-130 petition with USCIS along with a copy of your Certificate of Naturalization or US Passport and a copy of your birth certificate translated into English. If your step-father married your mother while you were still under 18 years of age, you can also petition for your step-father to immigrate with your mother. It will take approximately 1 year to process the paperwork before your parents will have their visa interview scheduled at the nearest US consulate. You can also petition for your little brother on form I-130, but it will take at least 10 years before a visa number will become available and he can immigrate to the US.

You can bring your mother, but it is doubtful you can accord the same to your mother's husband if they only got married after your 18th birthday.

You need to petition your Mom and the rest of her family (her minor child) should be able to come with her. The Step Father situation may have other complications involved but it may be possible to bring him depending on the details of your situation. Consult with an Immigration Attorney who can walk you through the process and help with the paper work.

You can file a petition (immigrant relative petition) for your mother. Once that petition is approved, you will then go through the rest of the process with the National Visa Center. Finally, you mother will have a consular interview and if granted an immigrant visa, she would be able to move to the U.S. as a permanent resident. The process usually takes about a year or so. As for your step father, no, unfortunately, you would not be able to petition for him. For a step-parent relationship to be valid for immigration purposes, you mother and step father would have to be married before you turned 18, and since their marriage took place recently (after you were older than 18 years of age), the step-parent relationship is not recognized for immigration purposes. So he won't be able to come to the U.S. with your mother. However, once you mother is in the U.S. as a Permanent Resident, she would be able to petition for husband. Also, for your brother, you have to file a separate petition, just like you would file one for your mother. However, your brother cannot immigrate with your mother as a derivative. This is something that would likely change if the Senate's immigration reform bill becomes law. However, under the current immigration law, your brother cannot be a derivative beneficiary of your petition for your mother. That means, you would have to file a separate petition for him which would be processed under the 4th preference category (which unfortunately has a fairly long waiting time). Additionally, once your mother is in the U.S. as a permanent resident, she would be able to petition for your brother, under the F2A category, which has a slightly shorter waiting times.

As a citizen of the US, you can petition your mother and she can immigrate immediately. However, because you did not establish your step relationship with your step-father prior to you turning 18, you won't be able to petition for him. As far as your brother, you have to petition him directly, but it will take many years for his petition to be current so he can immigrate to the US. He will probably immigrate quicker through a petition by your mom after she becomes a resident of the US.