FYI clicking the link in the middle of a lesson or practice will mean you have to start the lesson/practice again. Is it possible for you to change the target of the link to a new window or even "_blank"?
I know what you're saying, but... eh, not really. Using på is not as explicitly on top of as, say, ovanpå. Just like "on" isn't as explicit as "on top of". And vid datorn means "by the computer", not "near".
Do you mean it would have to be only radion in Swedish? Actually in Swedish it's more idiomatic to say lyssna på radio meaning 'listen to the radio' in English, I see I've added a link to further explanations elsewhere in this discussion.