Facebook, create an app, tab or link to site?

Have a website similar to yelp but smaller in scale and industry specific and
i want to connect it to a fb page. New to facebook tho and was wondering
which would be best.
1) Adding the search functionality to a tab on the page
2) Creating an app
3) Or simply add a link to the site on a welcome tab
I know the third option would be the easiest but i would prefer linking the database to a tab and just running off a fan page. Is this possible? suggestions?