Find out which client IP and Query using highest network Bandwidth from SQL Server
The DMVs sys.dm_exec_connections and sys.dm_exec_sql_text have most of what you need.  Try something like this:

SELECT TOP 10 session_id, connect_time, num_reads, num_writes, last_read, last_write, client_net_address, most_recent_sql_handle, x.*
FROM sys.dm_exec_connections
    OUTER APPLY sys.dm_exec_sql_text( most_recent_sql_handle ) x
ORDER BY num_reads + num_writes DESC


You might also wish to review some of the other DMVs, eg sys.dm_exec_requests and sys.dm_exec_sessions for useful information.