Hi Spenn55,
Welcome to the Mattress Forum! 
As long as your mattress is still supportive and not showing any excessive body impressions or sagging (which I believe it is not based upon your comments), choosing a topper is an effective, economical, and for some people preferable manner in which to create a more plush surface comfort to an existing mattress.
Take a look at the information in post #2 here and the topper guidelines it links to that will help you use your actual sleeping experience as a reference point and guideline for choosing the type, thickness, and firmness for a topper that would have the least possible risk and best chance of success.
Yes, they had their membership revoked due to issues with service, and they have since gone out of business.
Phoenix