Port forward.
Search for tut's here in forums or search your manual for your modem.
(it's not that hard)(usual port fowards are 7777 7788 7778 7770)(your choice)
You guys should do this:
Then type the default gateway onto the browser address tab, then a login box should apper, depending on what your router is the username and password could be different. You can check your router's username and password onto the bottom part of your router or in the case that the router come with. Or you can try finding your router's passwd here. If even those are not helping "******" other sites about default passwords.