In your case, I would suggest that you stick to your kit lens. The focal range is just nice lanscape, and should be pretty useful for most portraits. Find out what is your prefered focal length, as well as use the opportunity to understand more about the technicality of photography before plunging more $$ into this hobby.
Maybe you can add in a 50mm f/1.8 ($130+) for your portraits. It'll be useful for lowlight and gives rather nice bokeh.