Re-dyeing Hair?

I have gone from golden/platinum blonde to maroon, 2 weeks ago. The red already washed out, but I really liked the dark brown color. Now it is at this medium brown with my roots still semi-maroon. I would like to re-dye my hair to a rich dark brown color instead of the maroon. Now, before I went from light to dark the hair dresser I went to said that my hair was pretty damaged from lightening it. My curls have taken quite the toll so I don't want to keep re-dyeing it and be sorry. Is 2 weeks long enough to go darker or should I wait longer? (I was going to box dye my hair).