To move yor photos from the iPad to the new computer, PhotoSync works well. There is a companion program for the computer that will improve how it works. It is still worth your while to try and recover the old drive as suggested. Photos synced to the iPad are rarely the same quality as the originals.
Go into Preferences in iTunes, and under the Devices tab, turn of auto syncing. That way you can connect the iPad without worrying about whether it will overwrite all your stuff.
Now you can connect your iPad to iTunes and try the Tranfer Purchases option. If it does not transfer all your media, then don't sync. You'll need to find another route. Otherwise, you're good to go. Any musc synced to the iPad through iTunes (purchased in the iTunes store or not) should transfer.
Music or media in apps other than the iPod, Video, or iBooks app (third party stuff) should not be affected by a sync, as long as the app themselves get transfered to iTunes. Make sure the apps are transfered, and make sure they are set to sync (Apps set to sync and checked in the Apps section)
If you accidently remove the apps, the media in them will get deleted too. To protect against this, do a backup before syncing. Then save off that backup to a different place on the computer, to prevent accidental overwriting. You can find out where backups are stored here:
iPad: About backups