Please help me reconnect my Canon MX860 wirelessly to my iMac (AGAIN!!!)

Hi, I a got my iMac back in February and have been having constant intermittant trouble with my wireless printing from my Canon MX860. It will work for weeks without fault and then all of a sudden there is a communication error and the printer cannot be found. I have tried yet again to reboot the router, reinstall the driver, rerun the IJ Network Utility tool which finds my access point and takes me right through to adding printer but then there is no printer displayed to add. This is driving me nuts as this is the third or fourth time I have wasted days trying to reconnect this printer wirelessly. And this time I am having no luck. I've seen heaps of answers from PAHU and would appreciate any help he/she or anyone could give me.