It does sound like your hair needs TLC. Curious, did you use a boxed set hair dye? If so, that is where the problem lies. The volume of the developer in those boxes is 20. You needed a volume 10 which is deposit only. Also, you need to keep in mind that ALL hair colors have a base of yellow, blue or red. Blue being the smallest molecule and red being the largest. Hence why it's hard to keep hair red. I'm guessing that you were a bright yellowy blonde and that you used an "ash brown" to try to go darker. So basically what you did was "lift" your hair folicles and deposited blue ones. Anything with the name "ash" in it means it has a blue base, it's a cool tone. That's why your hair turned green b/c you were trying to lift and deposit a color with a blue base.
here is a color wheel that will help you if you can't afford to go to a salon:
http://www.clairolpro.com/hair-color-techniques/basic/color-theory
that will explain exactly what I just told you.
The quickest way to fade a dye job without buying a dye removing kit, is to wash your hair with dawn soap, it will take a few washings. But now that your hair is black, you want to go lighter, which means you need to "lift" color. So if washing your hair with dawn doesnt help (and please for the love of all that is good, go get you some Redken Anti-snap), I would just go to a Fantastic Sams or someplace like that, they should be able to get you to brown with minimum damage. Coloring hair is like being a chemist! B/c now you wanna go lighter, which means lifting and for you, you would need a volume 30 at a minimum to get you to brown.
Honey just get yourself to a salon! LOL