Don't know about Austria. In Germany, people like to repeat old information. Most local insurance reps are talking with authority about things they know little about. They have never been to Russia and the client base that will go there is rather small. At best some of them remember some old info from prior to 2009. Germans like to insure everything and thus there are local reps at every corner. Most of them highly dubious, in the same category as used car sales men.

Go tell the cops..
 

Securing actual coverage from your insurance in cas of an accident is only half the problem (even if the most important). You also need to clear the police checkpoints. The Russian cops may or may not know about the green card, and they may not care. If they say that green paper that they can't even read is worthless, then you're up for a bribe, no matter what the law says.

A Russian insurance will always get you through (well.. unless you're pulled over by actual thugs, but that's another issue).

Laurent