There is some hope that gas supplies to Ukraine could continue from Russia through this winter. See http://www.aljazeera.com/news/europe/2014/10/peace-hopes-ukraine-after-milan-meeting-2014101862256859418.html
Part of that may be due to the infrastructure in Ukraine being tied to Crimea and the rest of Europe.
Part of that may be due to the monies that Russia will get. Both from it’s request for back-payments, and payments for future exports.
In any case, there is hope that winter will see Ukrainians staying warm.
As for the long-term, Russian gas may be on the way out. See this opinion piece on the South Stream gas pipeline http://www.aljazeera.com/indepth/opinion/2014/07/bulgaria-south-stream-russia-201471673831876818.html