@The Curr: Sometimes you have to wait for the right moment, and since the girl is going out with a friend of yours, it doesn't seem like you are going to have much of a window...so I wouldn't do anything unless you are sure that she feels the same way about you and you are willing to perhaps risk your friendship with your current group of friends.
I was in a position once, where I really liked someone, hooked up a couple of times, got with some other girls too, but it never felt right with the others (compared to with this first girl), however she ended up going out with a guy she said used to stalk him lol. We still talk every now and again, and honestly biding my time till she is single, and will make my move after an appropriate length of time.
On a separate note, is there a what's app thread here?