I am sure that you used the Apple ID on both devices. Since this way it will sync your personal data from an existing device of yours when using it the first time. In other words, you should have an iCloud. Every device you activate with your Apple ID will get your personal data from the iCloud. Since the iCloud came with the new iOS and iPhone 4S this is the reason it happened.
All you have to do is log into your iCloud with the same info as your Apple ID at Settings => iCloud
If it doesn't work then you should check www.icloud.com if you have it activated for sure.
Of course you have to let the device make automatic sync. This will only work if your device is pluged to charger and connected to a Mobile network or Wifi.
Hope I was able to help.
Settings > iTunes & App Stores > Apple ID > your apple id here.
Further down in settings, you have Automatic Downloads, switch Music:ON, Apps: ON and Books: ON.
You can also start App Store app > Purchased > and download the apps you want from your previous purchases.
Just make sure you have Wi-Fi connection if you download directly to iPad.