1.) How about integrating the game as freeware into the steam network via http://www.steampowered.com/steamworks/?
2.) Adding a donations option and using that to advertise the game via banners that could be made by the community via some sort of contest or something?
3.) Updating cs2d.com to look a little nicer and more attractive. maybe with a game-play background and some transparency in the windows and a nicer bigger logo, maybe add some youtube trailers or gameplay videos too?
5.) making it open source instead of modable? Idk if that would work out with hacks/being integrated into steam. then you could make a forum dedicated to the open source and attracting devs who would want to help out considering the fact that its completely free and open source?
6.) Updating the game with better updates like increased resolution and more construction options/choices. and just simply putting more effort into the game, and if money is the only way to promote dedication then that should be the way to go, otherwise you would have to rely on the community. and the community is mostly made up of kids here anyway so idk?
7.) And also to make people stay you could implement clans into the cs2d website to make the game even more competitive and addictive, besides all the deathruns and prison servers. and by implementing i mean like designing a fairly complex gui for clanrankings / leaderboards / matches that could be arranged via the website and tournaments that could be run by the community and dedicated mods?
these are just some from the top of my head, i think there is so much opportunity but the only way to seek it is through dedication which, like i said earlier, can come either through the community or through the dev/dev's.