CHANGSHA SOUTH TRAIN STATION TO THE TRAIN STATION BY BUS AT NIGHT?

I will be arriving at 8PM at CS SOUTH train station (high speed from Luoyang Longman). I will need to get to the local Railway station for an 11:43PM train to Guilan. I cannot find out how to transfer between the 2 stations.
Is there a shuttle or direct bus? If so,How long will it take? Do I have enough time between trains? What is the cost of the bus?
If I had to take a taxi,what cost should I expect??