There is a WinAmp overlay called 'overlaysong'/'overlaysongcooler'. This could be messed around with to disappear after a while, or to display songs in a different way.
As for the announcement, the best way is to make your own overlay - look at the announcements and copy/change one to say what you want. You can remove the 'finished=1' bit of code to make it stay on all the time, and just make it only display every 10 mins. If you need any help with this let me know on the Custom scene forum.
You can then start the overlay whenever R4 starts. Look in prefs.txt (with R4 closed) and you'll see a line:
key/R4_START+ addoverlay(find([name],[Sound Check]))
change 'Sound Check' to the name of your scene, save, and restart. You should now have it appear whenever R4 starts