Usually, beta languages have to fall under a certain threshold of reports before they will be added to the app. That's to get as many missing alternatives or mistakes in sentences out of the way first.

You don't need to be on your laptop, just use the web browser on your phone and you should be able to get on to the Russian course. I almost always do it on my Moto X Android phone, like right now, for instance.

I have noticed that both Russian and Esperanto are in beta, and Esperanto is on the app but Russian isn't. The Russian course is fairly new, I think that they are trying to make the course a little more stable before they put it on the app. Although, I think they did try updating the app to support it, because I've had the app since 2014 and I think I saw something mentioning Russian in an update in September or October. It could have been too buggy for the app at the time, but I'm sure they'll set it up to run smoothly soon.

Russian was released in the App a few days ago! (at least the Android version)