<human>: Condense the text into a few key points

Hi guys, I came here for advice since I have nowhere else to turn.
I have very hardly fallen for my best friends sister, who is currently in a relationship of about a month. 

We are alike in many ways, we show interest in the same things, etc. It's easier to say that we have very strong chemistry. I am fairly sure that she shares the same attraction to me but is not acting on it due to her relationship. She has even gone as far as to tell me that they are more like friends than dating. I would have a few options here, but here's where it gets complicated.

My friend is leaving for the navy in about a week. He is aware of the attraction and fully supports me, and would rather have us together than her current boyfriend, so that's not the issue here, regardless of if it's up to him at all.

Here's another kicker, I'm visiting here from another state. I lived in the current state for about 15 years before moving, and am back visiting my friend before he leaves. This attraction between her and I is newly found, but I've fallen very hard. It would suffice to say that I've never been this into a girl before ever.

 I'm going to be here for about another month or two, and am leaning toward moving back. I have a job available and waiting for me here with a decent wage and full time hours. It's just a matter of making the choice to come back, I'm practically looking for excuses to come here at this point.

What do you guys think I should do? Should I tell her about my feelings and see where it goes from there? Should I use my friend as a median? 

I appreciate any help guys!
<bot>: I have fallen hard for my best friends sister, he leaves in one week, I live in another state, she has a boyfriend.