Are you using Eclipse for this because you tagged the question with eclipse.
If you are using Eclipse just right click on your project select properties now choose android. You should now be able to select another build target. If you want to the API package change the checkbox from 4 to 7.
If you are not using Eclipse and want to use the Android console program use the terminal program android in the following way
android update project -p <path to project> -t <new target api level>