To update CUtePDF Writer, simply download the latest installer provided by the developers on the official website. According to the data on the page, the latest version is 3.0.
Download installer: http://www.cutepdf.com/Products/CutePDF/writer.asp
It's not necessary to remove the currently installed version since the package will overwrite the older files and install the new ones. This applies to the driver installation as well.
Note: Make sure to run the installer as administrator since system files will be used to update the drivers for the virtual printer.