If I were you I would keep saving my money and in the meantime read all you can, join a camera club, and take some photography seminars (the Nikon School hits most major cities every year; look in the back of Outdoor Photographer magazine). If you don't already have it, buy Photoshop Elements and play around with it.
Two good books are John Gerlach's Digital Nature Photography and Digital Landscape Photography. I have both and I took a workshop with the Gerlach's. The books are easy to understand and practical, not technical.
When you're ready to buy a new lens, consider buying used from the buy and sell forum on fredmiranda.com. If you buy a Canon "L" lens, especially a used one, you will be able to sell it for close to what you paid for it. If you buy new, I recommend B&H or Adorama.