I don't know enough about the database to know if your data would be in a consistent state if you restored to another database name and rebuilt the table from the almost 3 week old backup. If there is enough data that would have to be re-entered or lost it might be worth a shot. If there isn't a lot of work created by just doing a restore and starting over from that point I'd go with that.

You should also be checking your storage to make sure it doesn't happen again. Usually there are hardware issues when a database gets corrupted.