Command Line to transfer file between 2 different servers in different networks

Command Line to transfer file between 2 different servers in different
networks

I would like to create a batch file for Task Scheduler runs every hour on
taking following actions.
A. File "apple" in Folder "fruits" at Server A on IP Address/Network A.
B. File "apple" in Folder "fruits" at Server B on IP Address/Network B.
File "apple" from Server A will transfer/copy to Server B and rename as
File "apple_bk".
File "apple" from Server B will rename into File "apple_20130101_bak".
(combine time-stamp)
File "apple_bk" in Server B will rename back into File "apple".
Both servers are Windows Server.
Above are in different networks, how to connecting by using command line
and transferring the file?