Any results in the Ukraine short of quickly removing the government in Kiew resulting from the coup, would probably be a defeat for Russia as a pro western government for the Ukraine is likely then infuture with all the consequences resulting from that. (NATO,EU)
The time in power the interim government will use to lay legally and illegally the ground for successful pro western elections the next time they happen. And this with western support.
So an ultimatum to this government could be an idea. It should  step down and make way for an Russian backed interim government, which will schedule and monitor elections and the political process in the Ukraine then and in future.
If the interim government in Kiew does not act upon the ultimatum. Well, then...

Further to get clear that Russia considers the Ukraine as its area of
 influence also for the sake of its national security and will not
 allow the Ukraine to join the West.
This is policy of might, but don't think such would not happen in
the EU, where Germany pressed countries to this or that and as
a member of the EU as a country you are finally told by the EU
leadership what to do.

If  Russia wants to go for more I can't say much.
I am just an outsider writing comments based on limited information.