Dying over lightened hair at home

I dyed my hair a couple of days ago using nice'n'easy SB1, no bleaching beforehand but it's obviously got some strong lightening ingredients in it. My hair was light warm blonde at the bottom and medium strawberry blonde/ginger for the rest with my natural ash brown roots growing through. The result of the dye job isn't THAT terrible considering I put blonde over ginger but it has a strong yellow cast to it and the top is still quite ginger. And I look a bit like big bird when I go outside. I've tried using a purple toner but it's done nothing so I would like to dye over it:
1. How long should I leave either before dying it myself or before going to a hairdressers?
2. I would like to grow out my hair, but my natural shade is about 4 shades darker than my current shade and is quite ashy (which clashes with my warm but pink skin tone...like the blonde does....I can't win!), is it safe to dye it at home or will I go another funny colour? Would I be safer with a dark neutral blonde/light brown?