To change your pledge amount, please do the following:
1. Log into your Kickstarter account
2. Go to the ChargeCard page: http://www.kickstarter.com/projects/nomad/chargecard-for-iphone
3. Click on "Manage Your Pledge"
From here you can now change your reward level or, if you haven't done so already, increase your reward by $5 to account for international shipping.