Donate, spread the word, but also participate on the forums. There is a large amount of SOCOM/PS3 players there who are trying to shape the game into a SOCOM sequel. And honestly, their posts seem like the want more of a action based game than a SWAT/Raven Shield type game. So post/talk about features you liked in R6 and SWAT and make your voice heard.
I'm down for $15, wish I could also donate more, but I just don't have any more money.