I doubt you can easily automate this process unless you write your own application for the purpose; testing if the computer is online, uploading data to webserver etc.
However, file uploads are not to be under-estimated, and if you have access to the client computer (or someone with iq > 5 does) you can do this without too much trouble.
A couple of hints for the client machine; MS Excel or any other program able to export to comma, tab, semicolon separated data, a web-browser able to handle file uploads and ofcourse an internet connection.
The user of the client machine gathers whatever data (s)he needs, then go to a web-page, upload the CSV (Comma Separated Values) file, wich will be processed by some PHP script you wrote.. And then do whatever you like with the data (insert into a database, perform some calculations, make some nice graphic bars etc)..