Nice bounty to be honest but why you don't spread it in this forum while it seems that you have a good amount of budget for the campaign? Its been around 3 weeks after you launch it, how many active bounty participants you have right now and how it affects your site? Is it effective enough? I just checked the site for a few minutes but there are only around 4-5 users betting with very small bet (1-10 satoshi only).
I believe you need to offer more than just bounty, you need to offer regular promo/contest to make people stay betting on your site. It is just unfortunate to see that you have enough budget for bounty but there is no good offers on the site.