Based on what you mentioned, I had no idea. It didn't make sense. But - I found a bit of the script online, and it mentioned that they were playing cards at the time. You didn't mention that, and that made all the difference! A queen is a card - and in many games it is a reasonably valuable one. (edit) I just read Zach's comment. My interpretation is slightly different - I think she was pretending to want to cheat, by asking the dogs if they had any cards hidden, that they could give her.

I had to find a clip of the movie to look this up. When the girl sits at the table, earlier in the scene, there are playing cards on it. The two women were probably playing a card game before she arrived. It looks like the actress is about to draw a card, and wants it to be a Queen (Q). Of course, it is random, but she is pretending that the dogs can decide what the card will be.

And of course, Mummy is an endearing way to say Mother :-)