She became Muslim and got married, but herm other is still receiving a pension

Firstly: 

We congratulate you for this great blessing, the blessing of Islam and guidance. We ask Allaah to make you steadfast and to help and guide you, and to guide all of your family at your hands, for He is able to do that. 

Secondly: 

Concerning the pension, reference should be made to the rules concerning it in your country. If the rules state that it should be stopped or a part of it should be stopped when daughters get married or when the children reach a certain age and so on, then they should be followed. 

If your getting married or becoming Muslim means that your mother will lose her pension, then you should explain that to her and advise her to inform the department that deals with that. 

We advise you to read Qur’aan and learn the rulings of Islam, and offer prayers on time, and treat your family, relatives and neighbours well. 

We ask Allaah to help and guide you. We would be happy to answer more questions from you. 

And Allaah knows best.