There are 2 methods for Terraclassifieds update.
Method 1
You can just click Update in your plugin's list. This button will be visible as soon as the new version will be available.
Method 2
You need to download the recent version of TerraClassifieds plugin here.
Then just unzip this package and run your favorite FTP client.
Navigate to wp-content/plugins of your Wordpress installation and just override terraclassifieds directory using extracted earlier package.
That's it. You have the latest version.