too bright

I colored my roots using Goldwell Topchic and added too much KK mix and my roots are now way too bright.  I want to tone them down.  Does anyone have any advise on what to do too recolor and get rid of the brightness so that my roots match the rest of my hair which is like a level 8 copper color with highlights (I can't afford to get the highlights done every time I need to cover my gray roots so I updated the highlights ever 2 months over so and just use a single process Goldwell 8K, 6N and sometime 6K mix on the roots in between.  Although that sometime comes out too dark so I tried leaving out the 6K this time and added KK mix instead but that was a big mistake).  Anyway, If you can tell I am not a professional so I could use some professional advise.