I've personally recommended purplemath.com to many students, who've reported back that they've found it most helpful. I recommend that you work through the lesson modules there, starting with the most basic ones (which cover what are essentially "pre-algebra" topics).
You might also want to consider a book (remember those??? those things printed on paper??). I recall seeing some programmed learning Algebra books, which are designed for students working on their own. You might want to check your local bookstore or an online book seller. You may even be able to find something on the order of Algebra for Dummies!
You may find it helpful (or even necessary) to hire a tutor who would work with you face to face on topics which you find difficult. If you can get a sample of the test you're required to take, a tutor could work with you on the topics you need to master for the test.