Fireworks techy work - tidy up exisitng logo and ensure it works on the web

Please see the yellow triangular logo at the top left hand side corner of this web page:
http://www.marketdata.co.uk/exchangedata/index10.php
Does it look fuzzy to you? On my PC here running ie8 it looks fine but when I view from another PC on a customer site running ie8 it looks fuzzy and the diagonal lines are jagged.
The logo was created by me in Fireworks MX v6.0 and I can supply the *.png file if required.
The intention is to define a task that will be quick and easy to carry out by someone who knows the technology well (I don\'t). I suspect the reason for this intermittent fuzziness is some lack of technical understanding by me.
The task will be complete when the following is provided:
1) new *.png file of logo looking very similar to the one above with transaprent background
2) new *.gif (or other suitable format) to be used in the web page with html to be used (may be important to get the size right?)
3) the above are tested on www.marketdata.co.uk/exchangedata/index10.php and do not show the fuzziness.