First you need to install the application and use your old activation key. If you receive any error related to activation, then you might need to re-activate the key or purchase the application again. The problem is that there is a small chance you'll going to accomplish this because the main website who sold the application is completely focused on another service. You can send them an email asking about the product, but I doubt that you'll get any help with your application since they are in another field of work.
Contact info: http://upperspace.net/contactus.aspx