Avaliable off the shelf from hamcity.com I would think - they tend to keep a loads of duckies in stock. Or Motorola, but their retail prices are shocking!
Or make one: you'll need a piece of stiff wire or bicycle spoke (better), a piece of dowling, or copper tubing (if you going to use a bicycle spoke - easier to coil when hot), a coaxial connector of the same type/oppisite sex that is on your handheld, some solder wire, beg, borrow or steal a soldering iron - get the measurements/dimensions off line or I'll attach them to email with diagram and happily send to you. That's it.
How long will it take to make?
About 20 - 30min of your time - you'll learn something, have the pleasure of using an antenna you made yourself and so long as you adhere carefully to the length and coiling dimensions I assure it'll work as well as (if not better than) any commercial ducky.