There was a thread talking about sourcing axe handles a couple of weeks ago if IRC. However, you can get decent hickory (or sometimes ash) axe handles in most farmers' supply shops. If you search for the nearest supplier of Faithfull Tools on their website you should find one within striking distance.
Your axe is fitted with a curved fawn-foot; the Faithfull axes handles are curved fawn-foot ranging from 12" to 36" in length and a wide variety of eye sizes. There's no such thing as 'the wrong shape' - it's a matter pf preference for the job being done (unless it's a double-bit of course).
You can also treat the handle as a canvass and modify it to suit your own preference.