Hi Hans,
We're glad to clarify this for you.
The AVG Internet Security is the paid version of AVG Antivirus Free.
AVG AntiVirus Free includes our intelligent antivirus features that detect viruses, malware, spyware, ransomware, phishing, and other threats in real-time. Whereas, the AVG Internet Security comes with all features included in AVG AntiVirus Free, and includes additional premium features for use.
For further information regarding the AVG Internet Security, please refer to this article.
Regarding the upgrade of your AVG Internet Security to 2 devices, please use this link to contact our sales team live chat. They'll help you with the upgrade.
Let us know if you need further assistance.