SEO techniques can also be done for free by webmasters, if you know some tricks. There are lots of guides out there if you or your associates wish to investigate them. Having bloggers blog about it, Facebook dealies, guild funky stuff all help too. In the end the SEO has to be backed up with great content, so keep working at improving the game as always.
P.S. In the longer future, making the game mechanics as a whole more customizable and variable (units, cities, maps, etc.) will be paramount to Dawn of Fantasy's success in my opinion, but that's for another thread.