Well that's simple enough when mIRC starts have the Ram usage on a timer like when we check the idle time. As for the song, when you slect a song get it to write to a panel, remember you're allowedtouse colour on these status bars, using +c. +p makes the statusbar panel appear popped up.
And when the song ends (The on MIDIEND, on WAVEEND, and on MP3END events trigger when mIRC finishes playing a sound) simply write again to the statusbar no song playing or something.

All the best,

-Andy.