XCode 4.6 will not support iOS 7 by any means. You will only be able to build iOS 6 apps that will run on iOS 7, but you will not be able to use new iOS 7 SDS features.
If you want to support iOS 7 features, you need to use Xcode 5. This might also cause some visual issues in your app.
My suggestion is to migrate to Xcode 5 and then check that everything is ok in your app, or do the required changes so that it works fine on iOS 7.
In any case, you can safely go back to Xcode 4 from Xcode 5, if you see that anything does not work out as expected.