You're off to a good start, but yes, those are both a bit underexposed, but that can be corrected in a good editing program such as Photoshop Elements. Don't feel bad about only liking two out of a hundred -- the nice thing about digital imaging is that you can really learn from it and experiment.
A true macro lens is usually a prime lens, not a zoom, and it is designated as being a macro while also suitable for other uses. For instance, the 105mm Micro (Macro) that Nikon sells can be used for general shots but then when one wants to get up close and personal, the lens has a very close focusing distance so that you can really get in very close and make the object look large in the completed image. Some zoom lenses have a closeup or macro kind of feature, and that sounds like what you're describing in your new lens. Also with some long telephoto lenses although you can't get in too close physically with the lens, you can zoom in pretty tightly so that it becomes a closeup of the subject and the background around it fuzzes out. My 70-200mm VR, for instance, is great for that. I can zoom in on a blossom on a tree branch and fill the frame with the subject while the rest of the background (other flowers, leaves, limbs, etc.) are all blurred very nicely (the 70-200mm has particularly nice bokeh). That 70-200mm VR, however, is not considered a macro lens.
Books: Here are three titles which I have found to be very good and extremely helpful:
Busch, David D. MASTERING DIGITAL SLR PHOTOGRAPHY (Thompson Course Technology, 2005)
King, Julie Adair. SHOOT LIKE A PRO! DIGITAL PHOTOGRAPHY TECHNIQUES. (McGraw-Hill/Osborne, 2003)
Sammon, Rick. RICK SAMMON'S COMPLETE GUIDE TO DIGITAL PHOTOGRAPHY. (W.W.Norton, 2005)
There are many others available, including one by John Hedgecoe, who's been doing books on photography for many years, and there is the classic by London and London, PHOTOGRAPHY, which is the one most often used in photography classes.
Hope this helps! Keep shooting -- that's the best way to learn.... and have fun while you're doing it!