On the matter of doing this yourself, I agree with Lars: not a job for a novice. I've done it many times and its still a little too easy to make a mistake that could cost if you're not careful.
That said, I'd also suggest that you think instead about moving your large "media" library to an external drive. Oh, and purge your library of things you don't actually listen to/look at, which is a good habit to get into long term (otherwise, you'll just keep needing more and more storage, making for longer and longer backups ...)