I agree with Freddy on the black background – hard to read in my opinion.
I also think Simmo has some valid points about the content of your site – look at many of the top casino portals, they have great layouts in my opinion and is easy to follow (go to Google and type in the big keywords).
Maybe you should also incorporate a news/article section quite prominently as this would change frequently, hence making visitors come back compared to displaying bonus offers that don’t change that often and can lead to the attraction of the wrong type of player.
Hope this helps……..