My script ends with a stalker a tune humming softly, while she glues pictures of the object of her obsession to the wall.

She's fixated on him - certain that he loves her the same way that she loves him; wants to take care of him (she feels he works too hard), etc.

I want the show to end with her singing a few words of the song she's humming.

What sort of song would my crazy stalker-lady sing to herself while she glues pictures of the victim to the wall?

Death toll: 7 named, about 181 unnamed

I personally would suggest Every Breath You Take by The Police. This is THE stalker song, IMO. So much so, that I call it The Stalker Song instead of it's proper title.

Try "White Flag" by Dido - I think the lyrics would suit, plus the scene you described made me think of it immediately because of the way the video ends - although both parties have pictures of the other.
Here's a link for the video too,

http://www.youtube.com/watch?v=orx16DiZtVE

Thanks for the suggestions! I ended up using "Won't Go Home Without You" by Maroon 5 (and then I read on Wikipedia that "The guitar undertone in the song is based on the The Police single, 'Every Breath You Take'..." which seems somehow wildly appropriate!)

I like "White Flag", though... maybe the radio can play that and then go into the Maroon 5 piece. *runs away to plot some more*

Death toll: 7 named, about 181 unnamed