It sounds like you want someone else to pick her up for you dude... Do you not have any inner game/personality? I don't mean that in an offensive way, so don't take it as such. Its just you've been given sound advice by J Smooth, short of someone telling you exactly what to type to her there's not much more help we can give you.
I mean, feel free to get her IM and then give me your login details and I'll pretend to be you and talk to her

But I dont think thats what you actually want.
Even so, if I were in your position, I'd get her to add you on IM (not vice versa, I like to make them chase), then as soon as she adds you say hey really quickly, then say you're going out to do something (maybe DHV) and either go out or just block her for a bit/set your status to away and ignore her (keep her waiting). Then when you come back I often go with something like "I'm back! Did you miss me? Aww, you did! You're so sweet, but dont get too clingy". Then I'd fluff talk for a couple of minutes, not long at all just like the basic ''how are you'' ''what did you get up to today'' bullshit, then I'd say something like; "this is dumb, we're doing all this talking to each other but we're not really learning about each other at all. I wanna get to know you properly. I've got an idea..." - then I either run the cube on her, ask her rapport questions (theres a thread with 6 great ones on these forums somewhere), play the 3-second-answer game (anothe post on this forum somewhere) or just any other cold read/rapport routine/game depending on how I feel. I think this kind of thing would work really well with the girl you're talking about as she seems like she already feels connected to you, build on that comfort and DHV as much as possible. All the time just throw in the odd negs. Also, try not to be online all the time, if you're online and she's online and you're not talking, thats normally bad, keep yourself scarce so she'll keep on wanting more.
Other than that, use your brain mate

good luck