well try link exchanges, with the right company these work really well, but apart from that you are probably going to have to pay for advertising sometime... if you want to do REALLY well.
if your posting on forums on a regular basis - you are not doing it right... there are no links in your sig here... so its kind of pointless
as mentioned above, link exchanges are also a good way of free advertising
you can also setup a small form on your site for users to fill in their email address to be notified of site updates and new content... you can legally send them email then everytime you do make an update... thats free traffic
