If you're looking for a combination of filters or the like to "undo the blur and make it look sharp," in my opinion that would be a really tall mountain to climb. Repaing this (and ones like it) will require a lot of (skilled) hands-on work.
Do you have any non-blury photos with the newlyweds positioned similarly? If so you might be able to get away with cutting out portions of various in-focus images and paste / blend / scale the in-focus pieces into this one.
Another possiblity would be to (literally) paint back the detail, using
PSP's painting tools. I don't have the skills to do this sort of thing, but there are certainly those who do.
You might be able to get away with turning this one into an abstract "photo-art type pic," which might fly with one image, but not several.
Sorry I don't have a magic bullet. Hope one of the other regulars will have better suggestions than these.
~DannyR~