You mean Mitsuki from FULL MOON O SAGASHITE??
My friend would have an absolute SEIZURE of excitement if she saw you at a con...she's obsessed with that anime/manga and loves Mitsuki. XD; And whenever I look at cosplay books she's always like "OMG IS THERE FULLMOON COSPLAYERS ASJDHALSK"
Anyway, back on topic. I think besides tying it in Mitsuki's style you need to do a little more to attain the look. If you see your hair is more in lots of little curls and it's brown, but Mitsuki's hair is tied in two large curls and her bangs are straight. She also has those two little wisps of hair around her ears, plus her hair color is black.
Unless you want to straighten, recurl, and dye your hair (which is bound to be harmful to it and I don't really recommend), I think a wig would help out a lot. A load of cosplayers use wigs, and they're very helpful for attaining hairstyles/colors that are very different from your own. You could get a wig with the right color/bangs and style it for the curled parts.
Good luck! 8D