Lightening a bad bleach job - HELP!

Hi! I have recently had the front of my hair bleached (two very thick streaks in the front).  It had to be double-processed because my hair is very dark brown, almost black.  The dark color is a home colorant (L'Oreal Preference or Excellence - can't remember which - but it is a very soft, shiny color...not damaged at all.) However, the blonde is still very brassy and I am not happy with it. The stylist put a toner on it, but it didn't help much.  What I need to know is...can I put a blonde home colorant on it to tone down the brasiness and lighten it up without turing it to mush? I used to (back when I was coloring all my hair blonde by myself) use bleach and then L'Oreal Excellence Lightest Natural Blonde colorant afterwards, and it turned out ok. Just not sure how it would turn out, since it's been double-processed.  And I DON'T want to have to go spend another $80 at the salon - that was ridiculous! Please help! :)

Thanks for the advice!  The Light Ash Blonde is more what I was going for (10NA)....do you think tht would work? Since there's no lift, will it still turn out close to that color?  There's a few small streaks of an orange-y color, but most of it is close to a banana yellow.  My roots are light, and not as brassy as the rest (since they didn't have the dark colorant on them originally.)  What do you think? 

Thanks for your help!!!