Come along to our SAS club meets at Pimpama state school. Plenty of members who can help out then you could bring your scope out to our dark sky site at Leybourn. You will see a huge difference then. You will never get results like you see in images at the eyepiece. If you are seeing Jupiter similar to the link you posted then thats doing very,very well and planetary observation is not really affected by light pollution more the "seeing" or atmospheric stability, which could look like focusing issues to you. Also too much power like using a 3x barlow is going to cause you heaps of problems with your viewing, try stepping the power down a little and only use a 2x barlow as too much power only make the unsteady atmosphere look like soup! A smaller, clearer image is far more satisfying than a big blurred image. Those fantastic images you see Mike and others achieve are done at very long focul lengths but they use fast CCD video type cameras running upto 60 frames per second so they can grab some frames of near perfect clarity when the seeing freezes for the split second or so,you can't detect this with your eye. Deep sky "hates" light pollution so dark rural skies are the go there.
Go to
www.sas.org.au
Matt.