This is an Immigration question. I will change the category. You may need to re-post.
If this information has been helpful, please indicate by providing feedback that the answer was either "helpful" or "best answer" as appropriate. Legal Disclaimer: Mr. Candiano is licensed to practice law in Illinois and Indiana. The response herein is not legal advice and does not create an attorney/client relationship. The response is in the form of legal education and is intended to provide general information about the matter within the question.
You can use your assets to make up the difference between your income and the minimum required to sponsor your mother. Read page 7 of the I-864 instructions for more information on how to use your assets.
Alternatively, you can ask another U.S. citizen or permanent resident who is at least 18 years old and is living in the U.S. to be a joint-sponsor with you. Read page 9 of the instructions for more information on joint sponsors.
If you have read the instructions and still have questions, I suggest you make an appointment for a consultation with an immigration lawyer who specializes in family-based visa applications. A consultation can be a great way to get your questions answered even if you decide to complete the process on your own.
This is general information only and not intended as legal advice. As AVVO makes clear, my answering this question does not create an attorney-client relationship. If you need legal advice, please seek out a qualified immigration lawyer who can guide you based on the facts of your unique situation.