Best website search?

So, I’m using wordpress to create a webpage for this student group I’m in, and would like to add a ‘search this website’ functionality. The problem is, I want to be able to search pages as well as posts, and have the search results ordered by most relevant content. I have heard that the built-in WordPress search orders results by date created, but when I tried using the Google Custom Search option, it seemed to ignore all my pages and just search posts.

Does anyone have any suggestions?

Site is here, for those who want to know: spba.stanford.edu