1. Too much hidden information. The main page should specify the pricing because that's the first thing we all look at. Yes, I know about the pricing page. But a click away is one too many. And I couldn't find a list of supported countries. If I don't know the cost and if I can get it, I'm not going to waste time asking.
2. You're cheaper than FastSpring now. But when FastSpring started it was a lot cheaper and more dynamic. You're competing with PayPal, not FastSpring. And PayPal is charging 2.9% + $0.30. So start where FastSpring started, not where it is after a couple years of growth. A bonus would be to find cost-effective ways to handle different price points. A 5% fee is ok for a $5 sale, but for a $1000 sale it's a bit too much.
3. Not sure how to say this in a more diplomatic way, but your store forms look spammy. Maybe the cluttered elements, maybe the asymmetrical design. You should talk with a designer and create something cleaner and nicer. The purchase forms are the last step of a sale. If they are not perfect, the client can easily change his mind. At least this is how I feel as a seller.
Good luck. And find ways to do things better. Innovation always attract people.