It is thoughtful of you, to think of your Mom's birthday. What you can give her, will depend on your budget. If you don't have a lot of money, make her a gift certificate, to clean the house for her, whenever she needs help.
If you have money, Mom's always like flowers or a gift card. Mom's forget about themselves and taking her to lunch or dinner, would also be a nice gift.
Does your mom like to read if so I would recommend a book if not then find out what her favorite movie or music is and get that that way you know that she will be happy let me know how you make out thanks