Giochi, an app with a lot of ideas to have fun and play with your children!

I would like to give to all the families the possibility to have content everywhere ( es. watch a video tutorial while I'm playing, etc..) and also give the opportunity to children to send me images or video.

I said Wow... seeing your app in the top list is amazing and gives you the energy to keep working on it.
My first advice is to organize the launch of the app very well.
Apps, are privileged in the ranking on App Store when they have been launched recently. So prepare a media kit, a press release, present it to your community asking for review and if you have the possibility, think also about an advertising campaign. 
You have to start to thinking about it at least 2 months before.

Without a shadow of doubt the chance of interaction with my community, thanks to the possibility to ask them to send me content using the app.

It might seem trivial, but be constant, always!
You have to take care of your app with the same, if not more, commitment that you put in your website.
The app should be updated (recording even video tutorials for example) and promoted, if not it will become a lost icon in the App Store.