If your wanting to dye it a.s.a.p i think the only think which is likely to work is to go a slightly darker colour.
Try the loreal kits, that are in a red box for about �10. I have used quite a few of them and love them, i did a colour called toasted coconut, which is a golden type blonde and it worked really well.
you dye it an all over colour then you put highlights in - might need someone to give you a hand as that can be a bit tricky.
Might sound a bit expensive for hair dye, but it works brilliantly. There is quitre a bit of a range of colours too. You could always try a light brown all over colour with light blonde highlights. - if you did that you might not get that many fine all over highlights so once you've done that you could get a kit where you get a 'cap' included (the thing you put over your head and pull bits of hair out) which will give you lots of fine all over highlights.
I recently did mine a dark brown (with the loreal kit) and used the highlight kit in with that, but i wanted some more all over highlights so i got just a superdrugs own highlight kit using the cap (it'll say on the box somewhere if it includes this) - this is a bit tricky to do on your own too but i managed to do it so you shouldnt have a problem. It worked really well.
i hope this helps :-)