Obviously colating a list of all the major news sites, game news aggregators etc. and sending out a press release or just letting them know a new version of FH2 is out is a good place to start.
FH2 is such an ambitious game, that has been around long enough it really ought to be on Wikipedia as well, and it's surprising that its not!
Fans should not hesitate to suggest a review of FH2 in their favorite Magazine or Game Site, and some nicely produced eCards that people can print, send to their friends, emails, post on fourms etc. also get a surprising lot of traction.
Similarly Fan produced DVD cover art for the game, formatted guides, and manuals adds another level of content that raises visibility and and credibility.
When playing other games, ask people in game if they've tried the new 2.4 release of FH2 -- I was playing Red Orchestra and was just wondered what the guys there thought of FH2 in comparison, ie. did they really like RO better, and was shocked that none of them had heard of it!
Standing on the roof of your house, late at night when it's quiet and screaming at the top of your lungs
'Forgotten Hope 2 is The Best Game In The World!' and spray panting that message on Police cars and public buildings is sure to get the game noticed as well...