You are already doing all of the right stuff.
When OIC first began (on its own boards) we had (IIRC) a three pronged approach.
1 - Gaming Days / Conferences - Getting involved in either organizing or playing in such events.
2 - Resource Development - Designing adventures, monsters, conversions, etc. to expand the quick and easy to use application of Iron Crown products. This can easily dovetail with #1 in that creating introductory adventures and premade characters can then be used in game days and conferences.
3 - Internet Presence - Internet banner exchanges, newsletter, webpage, etc.
There may have been more to it or some of this may be off, but it's the way I remember it.
Looks like you have all 3 areas covered.