Don't spend any money until you exhaust placement, room treatment and tone control options...especially room treatments if possible. Taming reflected sound could (maybe) give you the increase in detail you are looking for while cleaning up mid-range harshness. You'll learn in the process too!
After that new speakers would be the next thing to do...unless the Rotel is running out of power and clipping at high volume. Which begs the question... How loud do you listen and in what size room?
