Just a tip...the Strip's sidewalk will be littered with porn advertisements, and the guys who hand it out won't care if you're with a kid.
Circus Circus has an amusement park in it, one of the main hotels (I forget exactly, but I think it might be Montego Bay) has an aquarium with sharks, and there are a couple of other casinos with rides/rollercoasters. I've never been with a child, so I've never paid attention to the child-friendly places
As far as temperature is concerned, I was down there in January last year and I needed a jacket, but it wasn't so cold that walking around outside was uncomfortable. In fact, a sweater during the day was ok and the jacket was only necessary in the morning and evening.
Also, if your daughter likes dinosaurs, there is a place in St. George, Utah (about 2 hours north of Vegas) that might be fun for her...here is a link:
http://www.sgcity.org/dinotrax/indexmain.php