Upgrading your hosting service for more storage capacity is super easy.
1. Log into your account at www.hello.co
2. Click on your domain in the left panel, Active section
3. Look for the Services tab, and then look for the Hosting blurb.
You should see a button that says: Buy More
Click on that button and you will be sent to the next screen where you will be able to confirm the increase.
Complete payment, and... voila!!
Please note that increments are sized at 1GB per increment.