Have you tired using the Save for Web function to see what the file will look like before you save as .png or other formats? The other thing is it's only just over an inch and a half wide. You might try enlarging the live type which will not change the source file quality, and reduce the size in the Save for Web dialog. You have to consider where this is being viewed, It's the web and 72dpi type at 1.5" is not going to look great if you zoom in on each letter.
I have increased my AI document size (artboard) to 78cm together with the textual (width 77cm), generated a jpg with image reduction (in web export dialogue) and got this.
also i viewed this (4-up) before saving and this was the best result available, but still too fuzzy.
the above in b&w still fuzzy but not as bad, do you think it is my fill colour selection?
JPEG is not the right web (or similar) format for text or anything else that is meant to be sharp, especially when there is not a great multitude of colours.
The right format is PNG, or if you wish to please visitors with old (IE) browsers GIF.
The image should have Anti-Aliasing ticked (it is, or were in older version, hidden in the Image Size window), and you may tick Transparency to be able to just place it on a background colour/image (for GIF use the average background colour as Matte).
The way antialiasing works, the blend colors do affect it, but that's beside the point. The font you are using is simply a bit skinny and AI is the wrong program. You'd get much better results by using Photoshop or Flash and picking a different antialiasing algorithm in those programs' text options, plus you may be able to accentuate contours with layer styles to prevent them from looking degenerated.