Hi Voltron, I have tried both Raynox and tele convertors before. I can safely tell you, tele convertors do not give you the kind of sharpness that Raynox can. Not that I'm bias but I have tried all those because I cant afford a macro lens. There's is significant sharpness loss when you compare. The main reason why you have gotten a dedicated macro lens is not only because it allows you to go closer to your object for that 1:1 magnification, the macro lens is suppose to give you the crisp in your pictures compare to the "normal" lenses.
Besides using tele convertors, you can use picture editing software such as Photoshop to crop your pics to give you the magnification you want. Personally I feel that cropping a sharp image beats taking a less sharp magnified image.
All the above is base on personal experience, but dont take my words for it, try it out yourself to be convinced. cheers