Your best option is to buy or borrow a 1 TB external drive, back up everything, reformat your drive (you'll likely want to change the filesystem types for your data partitions anyway, which means you need to format them), and then copy your data back from the backup.
If this data is really that critical, you should have at least one backup already, so the above suggestion to buy/borrow a backup drive might not be necessary.
If you don't already have a backup, then you should REALLY re-think how critical this data is to you. What would be your reaction if you came home tonight, turned on your computer, and the drive wasn't recognized by the BIOS and wouldn't mount? If your reaction is "Dang, now I have to RMA the drive and go grab my backup..." that's good. If your reaction is "oh no oh no oh no oh no!!!", then you're doing it wrong.
Last edited by suicidaleggroll; 06-30-2015 at 01:49 PM.