Once again, I don't want to sound like I'm trying to minimize what you are going through....
However, you have to understand how eCommerce works. I work for a company that does IT support exclusively for banks, including security work. I've also worked on the web hosting side on the past. I'm not just pulling info out of my ass here. Evike does not process your payment, that's done through a payment gateway (typically authorize.net) nor does their shopping cart system display your credit card info for Joe Blow to see. While not impossible to crack by any means, someone talented enough to do that would not be working at Evike. It's not like skimming a card you physically have access to.
Neither the iPad itself or 3G is magically secure. If you look through some security websites, you'll see the the amount of people they pissed off when they started using iPad's + card readers to take orders from people in line. Invisible keyloggers for iOS are quite easy to come by and 3G is by no means a 100% secure system. Using a wireless connection of any sort to relay credit card information isn't the best practice. Once again, believe me, I've got no love for Evike. However this is the far more likely culprit.
When an eCommerce database gets hacked, they don't just take one credit card. If the gateway (authorize.net) got hacked, there would be a real shit storm. The fact that I haven't seen a mass list of people complaining, that points to you being the only person affected. A security breach only effecting one person generally points to an issue on the users side. I'd also wonder about the card company itself at this point. If this was an existing card that had never been used, they should have spotted this unusual activity and called you on it.
The reason I'm trying to argue/explain this is that as much as this situation sucks, it would suck more if it happened again with a new card because the same thing happened.
