How do I steal her away from her boyfriend?

I recently moved in with 3 hot girls in a house. They are all seeing people, nothing extremely serious. One of the girl who I like is seeing this guy who seems like the biggest and he's UGLY; I know for a fact I'm much better looking. On her facebook recently I asked her why it said she's single if she's going out with this dude. Now she erased that status, it doesn't say anything in her relationship status. She said she has "taken a liking to me" on a text. And she also expressed curiousity about what happen to me and my ex. We "kinda" cuddled once, using the same pillow while watching tv late night. How do i steal her away from her boyfriend? She's a tough cookie- she can get defensive at times and doesnt trust people very easily. How do I show her that I'm much more deserving of her attention?