I'd say pigtails.
buychina Amazon
Try ebay.com, they have a large variety of high quality cosplay wigs.
Hello Cosplay
Most cosplay wigs are meant to act as regular hair..so...yes.
Hello Cosplay or Amazon
This is all I can find: http://www.cosplaymagic.com/nashabcowig.html
Try looking up different cosplay sites and ebay.
Well, obviously. Unless your hair actually looks like hers..
Suggestions:EbayAnime cosplay sitesYour local anime storeYou can make it yourselfOr find a store online.
Look for wigs on Ebay. Or take a wig from a wig store that is the same color and style it yourself. www.wonderlandwigs.co.uk also do some good quality anime and cosplay wigs. Or standard wigs in a rang of colours which you can then style.
Are you going to a anime convention? You don't need to cosplay. It's not a must... unless there is a rule for that particular convention.You could just wear a wig and a cute outfit, and say that the character you cosplay would wear this too. Or just wear something similar. You don't have to look exactly like that character.