Your daughter's first line of help should be her classroom teacher. Many algebra teachers offer special help sessions before and after school. Also, high schools often have student tutors who can be a great help in mastering algebra.
It could be helpful for your daughter to do algebra homework with her friends if they truly work together on solving problems rather than having one student just do the problems for all of them. Having a tutor or going to a learning center can also provide solid help in mastering algebra. Also, is there another family member or even a neighbor who could help your daughter?
It is now almost the end of the school year and helping her will be tricky because in algebra each new topic builds upon previously learned topics. If your daughter has not truly mastered algebra, time should really be spent on doing so this summer. She could simply retake algebra in summer school. Or you could have an experienced tutor help her or have her go to a learning center.