Hi bal
Restore the GL from backup to a different folder. Then launch GL pointed at that folder. You should see the open batch.
Archive the batch under Maintenance | Maintain Archive Batches. The name is unimportant, but remember it. Then exit the backup GL.
Launch the live GL. Go into Maintenance | Maintain Archive Batches and change the Archive batch path to the backup folder. Restore the batch using the name above.
Steve