hi, yeh i do, im a hairdresser.
you must stop colouring it, do you do it yourself? please dont attempt to do this yourself.
you need a full head of highlights and toner. you will need to do this at least twice to get the result you want. it will have to be highlighted with bleach (as tint doesnt lighten tint) and then a toner put over the top.
it will affect the condition a bit so id advise you to have a bit cut off and invest in some decent home hair care.
be careful who you let do this, it could easily all go wrong.
are you in london? come and see me!! haha!
good luck.x