If the source (referenced) files were on the external hard drive that failed and you don't have backups of them they are gone for good.
What you're seeing are preview files of the original/source files that iPhoto uses for thumbnails and viewing at smaller sizes.
You can try taking screenshots but those will be good for little other than viewing on your Mac at the size they were recorded. They will be inadequate for printing quality prints.
What you experienced are the pitfalls of not having a backup strategy and using a reference library. Both of which are strongly not recommended.
If you can use disk recovery software or find a disk data recovery service that can recover your photos you can use them to create a new library - in the future it is strongly recommended that you do not use a referenced library and that you always have a good backup
There is no way to do anything except view your thumbnails on the screen in small size = you can drag the preview foldr to the desktop[, create a new library and impor tthem to iPhoto - but they are such low resolution that they will not be of much use