There a few solutions out there for windows hadoop client, I haven't tried any of them so, will defer to the community at large for specifics. One elegant/interesting approach that I will point out is the possibility of a flume agent for windows.
Tried and true method:
Off the top of my head, you can use file transfer method of your choice to get the files from the windows machine to a linux machine (SFTP, Samba, etc), and then use your favorite HDFS loading command/process to get the files into HDFS (hdfs dfs -copyFromLocal, flume, etc.)