What to do in NYC over the summer?

I'm going to NYC over the summer with my best friend, her mom, and my mom. We planned to stay for one night. We're not sure what hotel would be good to stay in that also isn't overpriced. We'll be spending one day sightseeing and we already know that we are climbing the empire state building if it's allowed, climbing the statue of liberty, and seeing ellis island. Are there any other attractions in NYC that we could do along with these as well? We are also spending our second day shopping and we want to know some stores worth while shopping in. We're only twelve so it's not like we can go to expensive, foregn stores like prada or gucci, but stores like Abercrombie and Juicy are okay.