Lucien, if you are on a budget, just use the lenses you have for now and then save money to buy the lens you want later. You will be changing 4 quarters for a dollar if you think that getting a longer telephoto zoom will make you take better pictures, or getting a newer camera with more megapixels will make you be more creative.
Sorry, but it just doesn't work that way. Sometimes people see some fantastic shots done by a pro photographer and then think that if they had that lens or camera they could do just like that. But photography is both an art and a technique. You could have all the tools and not be an artist. Your best investment for now (this is my point of view and does not involve Nikonites in any way) is that you should just keep practicing, reading as many photography books (specially older books that cover film photography and printing) to really learn how and why some techniques work in some cases and why they don't in others.
If you get caught in the "I need this cam or lens" way of thinking, you'll forever be searching instead of practicing. Just take more pictures, even if they are not great, take more, and more. Only experience teaches and it's really true that practice makes perfect.
Happy shooting until your budget is better to get the really great stuff that is way more expensive than the bargains on ebay.