Yes, this would be possible to do, but nothing like it has been created yet. For the now playing, the easiest option I see would be to have the script retrieve the XML from the shoutcast server for recent songs. To make a request, you will need something else between the Plus! Script and the database, probably a PHP file.
If you are unfamiliar with scripting, your first step will be to download the
scripting documentation. Look at other scripts too, to see how they operate. I wrote a tutorial that will be useful to you as well,
[Tutorial] Communicating with web pages