Colored red hair is too dark.

I have naturally light red hair.  It used to be brighter red when I was young but since red fades I have a light copper color.  I wanted my red hair to look like Marica Cross on Desperate Housewives.  I used 100% Color #764 from Garnier.  I only had it on for the directed 30 min. and my color is now a dark cherry red.  It is not at all what the color on the box showed.  So now I need to lighten it and was wondering if you can give me any ideas on what to do.  I was thinking about using Color Zap or Color Oops but I wanted to make sure not to take out all the color just to lighten it.  Or do I take out the color and start over since this is obviously not the Marcia Cross red I was hoping for?