Rated 5 out of 5 stars

==SOLUTION==
how to add Google Search (no plugin is needed):
1. Open Error Console (in Developer Tools menu)
2. Paste the following:
Services.search.addEngine("http://bwinton.latte.ca/Work/google.xml", null, "", {});
3. Press Enter
--- BONUS ---
how to add DuckDuckGo, replace the command:
Services.search.addEngine("https://duckduckgo.com/opensearch.xml", null, "", {});