Fairy washing up liquid can help fade it. Just wash your hair in it a few times. It can lighten it.
When you put the dye on did you have "old" dye on your hair already?
The picture on the box (and the name of the shade) is really just a guide and the outcome depends on your hair type and the colour of your hair - as well as whether or not you have another dye on there already. If you do, and put another one on it will automatically go darker even if the dye is meant to be pretty light as you get a build up of colour on there - and colour does not lighten colour, it only makes it darker.
Do you know if what you used was a permanent or a semi permanent dye?
If you want to do it again, or if you're thinking about putting another colour on there to actually end up brown (and if you would, always wait 48 hours at least in between each dye) do a strand test like instructed in and on the box. That way you will get an indication of how long to leave it on for (if you leave it on for too long it will go darker - unless you use a Perfect 10 from Nice n Easy as that will only have to be used for 10 minutes) as well as the outcome colourwise.
If you can't get the colour to fade, and it was a permanent dye, your only option, if you don't want to wait for it to grow out, is to go to the salon and have your hair stripped and repigmented before you can do anything else with it.