Safari is a browser, not a search engine.
To download it you should be using this link ONLY:
http://appldnld.apple.com/Safari5/041-5487.20120509.INU8B/SafariSetup.exe
Then double-click on the file to install it.
However Apple is no longer supporting Safari for Windows. My link is for the last Windows version, from 3 years ago, which was never intended for 64 bit architecture (which might be why you're having problems anyway).
In my opinion, Firefox remains the best browser for Windows. If I recall correctly (which is somewhat doubtful, as I frequently get ABers confused with each other!) you've already got Firefox. The default search engine (accessed from the box to the right of the URL field) is Google but simply clicking on the blue 'g' symbol (at the left of that box) enables you to switch to the Yahoo or Bing search engines. It also allows you to click 'Manage Search Engines', and then 'Get more search engines', to add DuckDuckGo or other search engines.