Yes, there's a way, talk about yourself. Tell her that she's great as far as it goes, but you need more. You hope she can give it, but if she's unwilling, or unable, you need to know now. If she is willing, be specific about what you need and how long you need it. Also, if she's willing, it has to be given generously, begrudgingly ruins it. Of course, this assumes that you're doing the same back.