you have plenty of time! you should be able to find one online, or definitely a salon or even david's bridal. some craft stores might have them too - they always have little bridal sections.
how about any of these?
Keepsake Hankies for the Bride and Family - Exclusively Weddings
Selection of custom linen products for the bride, including handkerchief, bookmark, bunwarmers, aprons, table runners, and more
Wedding Hankies - Mother of the Bride gifts-Wedding Handkerchiefs -Mother of the bride hankies- Hankerchiefs - Wedding favors