I cannot answer in Romanian but in English. Your mother needs to contact an experienced immigration attorney to review the facts of her case and determine if she qualifies for a waiver based on her being married to a US Citizen. The fact she overstayed three years will have to be examined. the B1 B2 was valid for use over 10 years but she was only permitted to stay in the visit as long as the I-94 allowed. Good luck.
Legal disclaimer: The statement above is provided by CC Abbott is based on general assistance and not intended to be a legal opinion because not all the facts are provided. The person requesting information and all others reading the answer should retain an attorney who is permitted by the state bar within the jurisdiction who can examine the complete facts and provide a legal opinion on your case. All information provided in the above answer and other information provided by CC Abbott does not create an attorney/client relationship within any state of Federal law.