let me try to decipher this:
You're on a wireless network (assuming a laptop), trying to access a printer on a completely different network (assuming a desktop), or
You're on a Wide Area Network, trying to access a printer separate Local Area Network
I'm going to assume the first one. It's a bit of a complicated process to get going. The easiest thing I could suggest is set up the machines for Remote Access (either built-in to OS or using a program such as VNC), use GMail to send files to yourself as attachments.
Let me know if this is along the lines of what you're trying to do. If so, and if you need help getting a remote setup going, I will gladly assist.