Assuming that there's no vulnerabilities in Apache like Goatboy said, you can't. That is, not without a DMZ server granting you access into the LAN.
For example, if I left something I need on my desktop at home, and I have a DMZ server running (*cough* http://plz.rewt.me/ *cough*
) running, I can SSH into that, and SSH into my desktop computer and get what I need. However, without that, I'd be shit out of luck. See where I'm going with this?
I also suppose something along the lines of a Squid proxy, or even an unprotected browser proxy like Glype would work.