After you create an EC2 instance and have installed all the software required and uploaded the required data, you can create an Amazon Machine Image (AMI), and then whenever you need to launch the exact same EC2 instance you can launch using the AMI.
To create an AMI, just click create image in the instances actions drop-down box.
In the EC2 dashboard:
Launch Instance >> Choose an AMI >> My AMIs
Now, choose your created AMI and proceed.