Your conversion fee is too high. Every company who does business like this is lucky to make back their initial investment back but never survive much longer after that, were as companies who enter into the market place to snatch up clients offer lower fees and once they have a solid foundation they slowly raise the fees. Think of this way, what's worth more to your business 100 people at 3% conversion rate or 10,000 people (maybe more) at a 1% conversion rate, then in a year's time as more and more people start getting on board you raise the fee.
It would be nice if you could find away to offer these cards in North America, not just Europe, and either in USD or CAD.