First of all, take the HDD offline. That means power it off (Turn off your computer) and do not use it, by removing it AND unplugging GENTLY from your computer and putting it in a safe, dry non-vibrating place. If this drive is the only drive in your computer, you need to stop using that computer.
Second of all, you must purchase a new hard drive! Save up for it if you must, you must have a new Hard Drive or SSD to save the data.
Third, you must wait until you have purchased a new hard drive for the data. once you have done so, you can take your computer offline again, and reinstall/re-plug in your drive, then bring it back online and copy the data over to the new drive immediately!