mewantsbitcoins, it's too expensive =) Whenever I run bots, someone find this and start slowly grab coins from them. Having no income from this project, spending hundreds on supporting bots is way too expensive at current exchange rate.
Sounds like you need better bots!
As far as getting people playing, perhaps it wouldn't hurt to have a lobby, where a person can see all the users who are online, or a list of users with online users at the top, and allow the users to "challenge" each other. It'd take some of the effort out of making matches. After all, even if there were thousands of users floating around on your website all at once, you'd never know it unless some of them sat down at a table to play. And the tendency, it seems, is not to sit down when one sees an empty table, but to simply leave.