The costume is on hold for me and I never quite got that far thanks to China thinking red hair qualifies as brown and sending me the wrong color wig. I did put together a jack sparrow costume though, and Penny Rose designed both. Odds are you won't find the real thing, you should start checking local bead stores for anything close and go from there.
Yes, head for a bead store. You may not find one bead that matches, but mix and match two different styles. The middle section looks like some spacer beads I have seen and cones look like they could be used on the ends of necklaces. Glue them together.
Getting it to stay in the hair may be something else entirely. The bead may also be glued in place.