Without China's help, Russia would already be having trouble financing war in Ukraine, @GordonGChang writes:
http://goo.gl/c4GKHC

It is estimated that Russia is spending approximately 20 to 29M USDs per day during the fighting and that since August 2014.

Simple math places the approximate cost since August at well over 3.6B USDs as the low end and 5.4B at the high end.