After you've washed out the dye, you may want to consider doing a hot oil treatment or two because your hair is very damaged. The dye is a conditioner but I still think it helps.
When you wash your hair, use J&J baby shampoo which will not strip all the color out at once. Harsh shampoos will make the color fade within a few washes. Some people suggest using a "coloring shampoo" (from the beauty supply store) if one is available.
Dont forget to wrap your hair in the dye towel when you sleep (if its long) or cover your pillowcase (if its short)
You can do minor touchups every few weeks to keep it lookin' good!