Hi Karthik,
You can change the default location of the metadata backups so they go to a different storage volume, which would be a recommended practice anyway. I don't think you can make it keep switching between 2 different locations (what's the reason behind this?). However, there's nothing to stop you having a separately scheduled job to make a duplicate copy of the backup if you need it.
To do monthly backups follow the instructions in the documentation: disable automatic backups and use a third party scheduler (cron, scheduled tasks, LSF, Control M etc) to schedule a monthly run of the script for an ad-hoc backup. I'm wondering why you need your backups to be so far apart?
Cheers
Paul