You cannot file citizenship for either, you must file for their Lawful Permanent Resident Status. For more information I suggest you speak with an immigration attorney. My firm is experienced in family based immigration.
If you are at least 21 years of age, you can sponsor your mother for permanent residence in the U.S. You can also sponsor your sister. However, the waiting time for a sister of a U.S. citizen to obtain a green card can range from 11 to 23 years.
You'll have to complete the I-130 Petition for Alien Relative. In addition to the age requirement (21 years old), eventually you'll have to complete the I-864 Affidavit of Support and be able to prove that you're able to financially support your own household and your mother at 125% the poverty level. The same form will have to be completed once your sister's priority date is reached (8-12 years).