I have the 18-55 kit lens that came with the camera (the pretty worthless one).
You have been misinformed. There is almost no such thing as a worthless lens, and certainly not the 18-55mm VR.
It is a very
sharp lens, with fast autofocus, VR, very little distortion, very close focusing and it's the cheapest "wide angle" (18mm, even though that's only a 36mm equiv.) you'll get on a DX body.
And any telephoto will have the same Aperture range as the kit lens (which I assume is what makes you think it is rubbish) until you get to about £600 for a low end fixed f/2.8 70-200mm.
And I generally wouldn't recommend buying a lens without some idea of what you want to get into, and I would prioritise around what you feel you're missing when you're out. For example I'd love an 11mm or an 85mm f/1.4, but can't justify the price as I only feel I would have used it a few times by now, and there are other tricks I can use to get similar effects with what I have, where as I feel there's quite a few shots I've missed due to lack of a tele.