What tint or box colour to use to get this medium brown?

Hello, I want to dye my hair permanent medium brown, just like the picture attached of Mila Kunis. At the moment my hair is a range of colours as your can see in the other picture. I've always dyed it dark brown and about 6 months ago had a blonde dip dye hence the lighter part.

My mum, an ex colourist will be dying my hair, she is capable but isn't sure as to what tint will cover the range of colours within my hair. She can get hold of the professional tints e.g Majirel, Koleston... and we don't mind using a box colour set either. We just need help with what colour to pick !!

If anyone can help that would be fantastic! Thank you

http://cfile24.uf.tistory.com/image/154E1E3D4DDCB94336A376