Young women do all kinds of things that make no sense. And I say that from having been one myself.
It seems that she is fairly confident since she will call a guy she's only known a week in the middle of the night and ask to come over to sleep with him. If she is confident enough to do that, she is likely confident enough to make a move if she does want to have sex with you.
I would guess that she feels "safe" enough with you to get some affection and cuddling, which she misses since she is still hung up on the ex, without feeling like it will lead to sex, which she is not ready for emotionally since she is still hung up on the ex. She may be debating an attraction to you and her feelings around her break-up.
The question is what do YOU want? If you care for her, like her, would want a friendship with her at the least, do not make a move. Let her come around to it in her own time, if she ever does come around to it. (I did once have a relationship that began this way, so given time, it could happen.)
If you like her but don't want to be used as a surrogate cuddle, tell her so. It's better to be honest and up-front.
If you really don't care at all, make a move. She will either reciprocate or she will get pissed and not use you as a human teddy bear any more.