remote desktop and DynDNS, it'll be slow as hell for transfering files, so and FTP server on your desktop machine will probably be the best bet... remember you'll have to setup port forwarding from your router etc. etc.
If you don't understand all that, pls don't priv me and ask me how to set it all up... I really don't have the time, and usually charge for that kind of consultation...
There is plenty documentation online and on this forum.