In order to edit your credit card details, you'll need to add a new credit card through the Billing Tab on your dashboard.
1. Log in to your dashboard.
2. Go to your billing tab.
3. Select 'Add Payment Method'.
4. To make this your new payment method, click the card you've just added and then select "Set Payment Method".
5. You can then delete the non-current payment method by clicking the rubbish icon next to the old card.