I need to dye my bleach hair back to brown..... Help?

It was a bit of a spur-of-the-moment thing, but now I have a really failed attempt at dip dye and it doesn't look too bad, but I don't think it's subtle enough for school, even though I only have 2 weeks left.

I've bought a dye, but I'm scared my hair will go green....
I didn't use toner on my hair so it's quite ashy - it's blonde, but there a trace of my natural hare colour.

What do I do?
Do I just use the dye? Or do I have to do something before so it doesn't turn green?

And do I have to do the 48 hour allergy test? I really need my hair back to normal by tomorrow evening....