Looking for Safari 7? Safari 7 is included with OS X Mavericks. To install Safari 7, download and install OS X Mavericks from the Mac App Store.
To keep Safari up to date, use Software Update to install the latest version of Safari available for the version of OS X you're using.
If you need to reinstall Safari, simply reinstall OS X. Use Software Update after you reinstall OS X to make sure Safari and other OS X software are up to date.