Hi! When you book Discovery Cove you will get admission to Seaworld for a max of 2 weeks I think. (I've had a season pass to Seaworld for 10 years or more and have been to Discovery Cove once). Honestly I'd recommend spending two days at Seaworld if you can spare one more day! It's definitely possible to go to all the shows and rides and animal exhibits in one full day, but you will be rushing from attraction to attraction with little time to relax and enjoy the animals. I can sit for a hour at the stingray feeding tank just petting the rays as they swim by! I think you would appreciate the second day to revisit your favorites and so you can spread out the shows. The shows are very re-watchable as well... especially the Clyde and Seamore Take Pirate Island show! The actors are usually different each day and you never know what will go wrong and make it even funnier!
There are plenty of hotels around the park, but I don't believe that there are any "on-site" like at Disney. (this could have changed though! I always stay in Kissimmee)