Okay here’s the steps to upgrade an existing Ec2 EBS instance to a larger box
1) Right click on the instance and select Create Image (EBS AMI). This will take a few minutes
2) Go to your snapshots and right click on the new snapshot you just made select Create Volume from Snapshot
3) Create your new EC2 (larger) Instance.
4) Stop your new EC2 instance
5) Go to volumes, right click on your volume from step 2 and attach it to the new EC2 instance (/dev/sda1)
6) Detach the volume auto assigned to the new EC2 Instance
7) Start your new EC2 instance