|Yes, it's a great shame to lose those memories. Best bet is to keep the card but don't use it again, against the off-chance that by some future method you might be able to recover more - technology is always changing..|
Otherwise about all you can do now is make sure that important files are well backed up - maybe twice. One of the most reliable methods is a small USB hard disk, this sort of thing:
You can get 500 GB for about 50 dollars on this particular website but best shop around. Depending on file size you could get 200,000 to 300,000 pictures on 500 GB so a small one, if available, might suit your needs.
As a parting shot I have unearthed another recovery freebie:
One of our posters managed to recover some files against all odds with this so it could be worth one last go.
Always pop back and let us know the outcome - thanks