teachermarites

You will not know until they send you a letter with the NVC case number. Right now, it takes approx. 35 days from date of approval to getting a case number. Call NVC if its been more than 35 days. Ours got approved on Dec 8,2014, sent to NVC Dec.15, NVC received it Dec 22 (according to the agent I spoked to) and until today, they havent created a case number.

I just got out of this loop few weeks ago. It depends on how complicated your case is. Mine, was really complicated and to correct everything took us almost 2 years from birth certificate correction to passport application.
If your mother was never issued any passport before, that's better. All you do is file a correction at NSO, no attorney or court order needed. Visit your local registrar office in your town. The most important here is that your mother's name in your birth certificate should match your mom's birth certificate and other siblings you may want to petition in the future.
in my case, my mother's name in her birth cert is completely different from what's on my birth cert and my siblings so what we did is to file name change on my mother's name to follow what she known and what is on most of her documents to be consistent. It will take about 5-8 months depending how fast you follow up and keep track on the process...
How did this happen? We don't know but it happened because Philippine system on registering names isn't as good as other countries.
To make matters worse on my story, my mom went abroad for few years ago with same name on her birth certificate, when she went back to the Philippines on January, she went right away to the DFA to change passport name to the new name and DFA asked tons of documents again, affidavit of explanation, discrepancy and all that... IT WAS A HEADACHE!
My two cents, fix it as soon as you can!

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Important Notice:
We are aware that some applicants continue to experience technical difficulties accessing Form DS-260, Form DS-261, or paying immigrant visa processing fees. Please visit this page for instructions on how to continue processing your case if you receive technical error messages when trying to access these forms. If you have an emergency need, please contact the U.S. Embassy or Consulate where your visa will be processed for further instructions. We are working to address this issue and apologize for any inconvenience.