Uploading different iphone/ipad application versions

Question

I've developed an app and released it for free on the App Store. Let's say its name is xxx I've now developed two new versions of the app:

• The first is for iPhone (paid)
• The second is for iPad (paid)

But now how can I upload these two new versions to have the same name of the free one?

Actually I need to release three apps for xxx, one for free, the second one for the iPhone (paid) and the last for iPad (paid).

If this is not valid please tell me what I must do.