As I always say, it's best to stay away from eBay for wigs. The quality is typically very bad, most photos are stolen, and unless you have a head a mere 21 inches in circumference, the wig ain't gonna fit.
I would look through the medium length wigs at Arda-Wigs.com. The fiber quality is top-knotch, and they will fit people with larger heads. I think this wig looks good for the character. http://arda-wigs.com/collections/eowyn
Finished: Armin Arlert, Mayoi Hachikuji, Tomoko Kuroki, Ultimate Madoka, fem!Masky
In progress: Kougyoku Ren, Lightning Farron
Upcoming cons: Sabakon, Youmacon, Con+Alt+Delete