red.. to black.. to odd brown

Hi!

In January, my friend had the crazy notion of dying my hair black. (I'm a natural redhead.. I don't know what I was thinking). So, we bought Garnier Nutrisse, because she had used it on her hair and it faded pretty fast.

Long story short, it was a cool colour for about a month, and now it's a very dark (and ugly) brown. My original red is starting to show through the cracks and roots, but the ugly brown persists, and has been since about Feb. I want my hair to be it's original colour again by July, is there anyway I can do this, or should I just keep shampooing like crazy to fade it? Thanks in advance!