You can change search settings in Firefox - add your own search engine if you want, if you do not like something.

- Yandex is much better for Russian / IT searches, google is good for everything else.

I think you may be wrong here - for Russian-content related searches Yandex performs better than Google. Although not being russian, i am russian native speaker, and use it in my searches as well as google in english searches.
Yandex seems to offer more relevant results, as well as they have better understanding of russian morphology.
Still, google is my main search engine (as english remains primary language for me these days).
Also, just to note. I noticed that for IT-related searches, especially programming, yandex/russian search results provide me with less, but better & quickier solutions to problems, than google, which returns tons of rubbish. Just my 2 "kopeykas".