You can buy and download this dictionary software from its official website. The currency is set to Euro and there are trial downloads available on the same site. Use the link posted below to reach the website, then identify the dictionary you need and press the bag icon (in red color). After you pay for the program, a registration key or a license file will be emailed to you. Use that to register the program and unlock its full potential.
Note: If the website shows Greek language, click the English flag on the upper-right section.