How do I fix input lag on my new HDTV

Input lag is generally controlled by the TV and generally not something you can affect yourself, outside of using "game mode". If possible, things like disabling higher than 60Hz display modes and any form of postprocessing can help display lag, but there's often no option for doing this outside of "game mode". You can try disabling any advanced video features the TV allows you to and see if that decreases lag.

This is why it's important to check the input lag of a TV or monitor before purchasing, as it's for the most part out of your control. Make sure you're not using a capture device device between the PS3 and TV as those can introduce lag as well; I personally use a splitter to get the feed direct to the TV and direct to the capture card. If you're using a splitter, make sure it's a powered splitter.

This review indicates the Kogan LED 55" TV might have upwards of 70ms of input lag, which is fairly bad.