Well you'll just need to convince your husband that you guys need another trip to Disney to take advantage of your gift cards! 😀 But as far as ordering online, it seems like most pins can be ordered from Merchandise Guest Services (over the phone or through email) at Disney's official pin page (I'm not sure if it's ok to post a link to there or not, but the url for the website can be found on the bottom of the backer card for any open edition pin bought on-site at Disney.) 🙂 Apparently, all you need is the sku (which you can also find through their official page.) You can select the location (like Walt Disney World) as well as the month/year of each pin's release, and the listings for that month come up. When you click on a pin you like (through the 'Read More' button), it will bring you to that pin's specific page, that will list the sku, the price, the release date, a description of the pin, and information for ordering it through Merchandise Guest Services. Not sure if you can use gift cards or not, as I've never personally ordered through them (since I live close to the parks, and can just take a ride over there whenever I want), but I'm sure if you contact Merchandise Guest Services (through their email or phone number, both of which are available on the official site), they'd be able to tell you if you can use a gift card, and if so, how to use it. That may at least expand your options for being able to purchase new pins that aren't available on the regular Disney store online, and without having to resort to e-bay and paying above retail for something new that's an open edition. 🙂
Hope this info helps!
-George