If you sync with your Mac or PC, then yournapps will be stored in iTunes. Syncing your iPhone should have transferred the app to iTunes. Then syncing your iPad should have transferred it to the iPad, unless you had set it not to. See if you can find it in the apps section while syncing your iPad.
Otherwise, you can always run the App Store app on your iPad, search for the app, and then add it directly to your iPad by downloading it a second time that way.
If you sync with your Mac or PC, then yournapps will be stored in iTunes. Syncing your iPhone should have transferred the app to iTunes. Then syncing your iPad should have transferred it to the iPad, unless you had set it not to. See if you can find it in the apps section while syncing your iPad.
Otherwise, you can always run the App Store app on your iPad, search for the app, and then add it directly to your iPad by downloading it a second time that way.