Hi,
The plugin comes with PureMart v3.0
If you have any older version, then it means, you don't have the plugin.
I am seeing that you are eligible to receive free updates. I just sent you your new download link to your email address. Download the ZIP file, UNZIP it and read the TUTORIAL.pdf. It will guide you the install the v3.0, and also you will get the plugin as well.
For the other extensions/templates you have purchased from us with "free updates". You can download the most recent versions from the "My Account" link in flexiblewebdesign.com
Cheers.