Option 1: Buy a pre-flashed card. These come up for sale all the time over on sites like Amibay, or you can post in their "wanted" section. Here's a post from someone looks like he still has 16 cards available for the reasonable sum of £15 + shipping, and links to a tutorial how to set it up:
http://www.amibay.com/showthread.php?71871-25-x-WIFI-CARDS-ZYXEL-WPA2-AES-AMIGA-A600-A1200-PCMCIA-WIFI
Option 2: Find someone willing to flash your existing card for you.
Option 3: Get an adapter to interface a PCMCIA card to a modern PC, and flash it yourself. Adapters can be bought at most computer retailers or online.
TL;DR. Just buy one of the cards from the guy in the link if you want to save yourself a lot of hassle. 
Mike, thanks for your recommendation
The card has been posted today.
@Punkyclown
Your card is on its way to you
Check your Amibay PM box
