|Typing in all caps is considered shouting and is therefore rude.|
You can't expand your c partition to include the storage space on the new external. You can just change the path where you save stuff to direct it to the new drive.
If you don't regularly perform backups of your personal files you will eventually be sorry to didn't.
You didn't indicate weather or not your computer is a laptop or not. If you have a desktop I recommend you add another hard drive internally and then use the external for backing up (making a second copy).