I can to translate into Russian, tough not a professional. Would you mind it? Sorry, I’ve very costly Internet, so I’m very brief.
Welcome to the forums, opalex. 
Avast has already been translated into Russian. Please see the webpage at the link below and scroll down to the paragraph titled Internationalization …
http://www.avast.com/eng/avast_4_home.html
Also, the download in various languages is at this link …
http://www.avast.com/eng/download-avast-home.html
Please come back often, learn more, and maybe help others.
If you could help improving the translation, send an IM to Igor and he could help you on your desire