The opening of the russian section on duolingo is estimated to 25/08/2015 (for the english speaker but i will try it ^^) https://www.duolingo.com/course/ru/en/Apprends-le-russe-en-ligne But in the meantime, you could try LearnRussian, it is not duolingo but it is a little interactive.
If you don't mind working hard, you could try "learning-with-texts". It's basically a free (but basic) version of lingq and you have to import interesting texts yourself. Then you can mark words (or groups of words / expressions) and learn them. Every word you don't know, is marked in a colour. The words that you do know, are regular text. You do need some computer skills though (setting up lamp stack / or windows equivalent, converting mysql connection strings to mysqli, etc...). Good luck! This is the link with download location and instructions: http://lwt.sourceforge.net/index.php
