If high magnification macro photograph is what you have been looking for, forget about buying a dedicated macro lens because your 18-55mm kit lens is good enough for the job.
What you need to buy instead is an extension tube and a reverse lens adapter so that you can mount the kit lens on the reverse for a super-duper magnification. You should also invest in a flashgun and a diffuser.
This is what I can conclude after watching this very enlightening video by Thomas Shahan on how to take high-magnification close-up photographs.
Although I might have understated the tricks he employed to his extreme close-up photograph techniques, I feel that this is the way to start for any beginner wanting to upgrade from shooting macro photographs using a point-and-shoot camera to shooting them using a DSLR.

{ 2 comments… read them below or add one }
I have an extension tube and I know how hard it is to shoot bug up-close. even the slightest move can spoil the focus. he probably tries hundred of time just to get 1 single good shot..
Inspired by the work of Thomas Shahan along with much patience, I have made pictures that I liked a lot, but I am still an apprentice.
This is one of the ones I like.
http://www.flickr.com/photos/martin-jesus/4606317855/in/set-72157624096631558/