Client File Retrieval

I am about to have my site switched over wordpress. Something that never worked well with DNN, An area where my cleints can easily retrieve their files from me.

Is there an easy to use/manage plug in that accomplishes this?

What I would like–
-a place(on the back end) where I can easily upload the content(mostly audio files)
-I can easily indicate which client it is for

…then

-it will automatically send an email to the client letting them know new content is available
-a place for the client to easily log in an retrieve their content

Again I am new to wordpress and just trying to work ahead after the site is built. Thanks in advance!