If you are trying to find it in game and are behind the same network it will always be in the LAN search area for you, but if all ports are forwarded correctly then it will be visible on the Internet search from in game for others.
Is it the same server in your sig? If so it seems to me that it is visible to the master server list.
When behind a network trying to make sure your server is up on the master server list use the STEAM SERVER LIST. Located under the Steam window> View> Servers, make sure to change the filter to Brink.
You can also try reading thru this other post already discussing this situation, which a simple search would have found it.
http://www.splashdamage.com/forums/showthread.php?t=28654