What is the expertise of this site and how far it is change from beta to normal?What's preventing it to change from beta?
One of the differences between a beta site and a graduated site is that upon graduation, the rep requirements for various privileges go up. The top critical permission (trusted user) is 4,000 rep on beta sites and 20,000 rep on graduated sites.
Typically, sites won't graduate until there are some minimum number of users with more than 20k rep. At the rate we're going, we should hit that mark in about two years. Though as time goes on, the number of voting users the gradually increase, so perhaps not quite that long.
Everyone can help the site reach that point by asking, answering, and voting.