This might be too late! I'm sorry! But if it's not I got Tthis wig:
but I forget if I got it in Chestnut Brown or Dark Brown. I love it. It's very comfortable, works with the character, easy to wash, and fairly inexpensive (though the shipping price was kind of high).
Again, I'm so sorry if it's too late! I saw this post a long time ago but never got around to replying. Have fun with Haruhi!