A true macro lens is about 60-65mm, but will cost you a fortune!
Regarding your last post, I wonder if you still have the settings on "auto".
Manual settings are sometimes going to be better for this type of shot, so at least if you can't get everything in focus, you can select which parts of your composition you do want in focus. I don't know if your camera also has aperture priority and/or speed priority, but this may be a good option as well.
Try this: set your camera to manual, then open a book and try focussing on a sentence roughly in the middle of the page at different apertures - take a few shots to see how your aperture affects the depth of field.
On the other hand, once you start photographing the bees, you will also need to take shutter speed into account - eg do you want a fast speed to show all the wing detail or a slow speed to give the impression of movement?
As a general rule, a fast shutter speed needs a large aperture, and a slow shutter speed needs a small aperture.
Having told you the 70-300 was not suitable, what is the largest aperture on it (ie the smallest F number on the barrel)? You may want to try this at the 70mm end of the lens, and your 18-55 at the 55 end.
The macro rings will reduce your depth of field considerably, as you have found out, thy are also likely to soak up a lot of light.
At least with digital you can experiment with very little cost and no waiting time, not like the "bad old days" of film.