dont panic! i have done this before and it went exactly the same.
you have 2 options really if you want to dye it yourself -
a) buy quite a few more packs of blonde dye (try swarzkopf ultimate blonde) and maybe a lightener pack too, this is what i did, took quite a few packs but eventually it went blonde - or try getting a pack of loreal colour expert, the big red boxes you dye an all over colour then put highlights in, try one of the blonde colours.
if you decide to do it blonde, and it will probably still feel like straw, just put loads of conditioner on it and this should help.
b) dye your hair a dark brown colour, which will *fingers crossed* get all the blonde out. again you could try one of the loreal red box things and use that - i use these and they work really well. The highlights look really nice too, if you want more highlights just buy another highlight kit (you can get superdrugs own highlighting kit).
another thing you could try which i have done in the past is get one of swarzkopf dye's in purple or red and use that over it, it makes it go quite bright - which looks nice actually - dont worry it will fade.
hope this helps, let us know what you decide to do with it :-)