There will be no way to do this (retrieve files stored on the computer at home) unless someone is there - assuming you do not currently have any remote access system set up on it.
I use
www.logmein.com for remote access - so can access my computer from anywhere as long as it is on. I use the free version and it works just fine.
The only thing is, though, someone has to be physically at each machine to set it up... but of course if someone were home to do this, they might as well email you the file(s).