Assuming you are a US citizen, you can now submit a separate petition for each member of your family (parents and siblings). At this early stage of the process, your income is not yet relevant when it comes to getting the petition approved. However, you will need to submit your financial information and documents to the NVC after they receive the approved petitions from USCIS. It takes approximately 1 year to process your mother's paperwork before she will be interviewed at the US consulate. As for your siblings, they must wait for the availability of limited visa numbers before their own process can be completed. It's currently taking about 12 years from the date the petition is filed before a visa number will become available. If your income is insufficient to sponsor your mother or sister when the time comes, you can recruit up to 2 more joint sponsors to meet the requirement.
Answered on Aug 07th, 2014 at 2:45 AM