Try using a color remover to take out color(My experince and pictures with color remover on my black hair http://www.colorzap.50megs.com/
) It works best if you can do it asap and not wait like 2 or 3 months.
What is your base color Blonde? Brown? Try using a red or neutral based protein filler found at Sally's before you color again. The instructions are on the bottle.
I've been through this plenty of times