@Joe Jackman I dont quite understand what u r trying to do here but im gonna take a guess. I think what u wanna do is add extra space to your linux drive and if this is the case its not as easy as just doing that. You need to install the O/S to that drive.
No, you don't. You can add a new drive, move your files over and then mount that as your new "/home/<username>". I've done exactly that on mine. My original installation was Linux on a 75 GB partition. I later added a 1 TB SSD and I am now using that as my home directory.