This sounds like you may be using an alternate driver to the Canon driver, such as ones available from Sourceforge called Gutenprint. These drivers do not show the Utilities icon in the printer queue window.
You can confirm which driver you are using by highlighting the printer in the Print & Fax > Printers list and then looking at the right hand pane. Here you will see the Location, Kind and Status. The Kind section will show what driver is being used. My guess would be that you have "Canon PIXMA iP4500 - CUPS + Gutenprint v5.x" showing here. Therefore you will not have the Utilities icon or the ability to check the ink levels with this driver.
To get the ability to check the ink levels, you would have to use the Canon driver for the iP4500. However, since you mentioned network printing in your original post, then you may not be able to use the Canon driver as it does have issues with certain types of network connections. So my advice would be to keep using the driver you have, since it is printing, and don't be concerned about the ink levels. The machine will not print if any colour tank is empty - this would risk burning out the print head. So, if the machine doesn't print, then you can check the inks just in case they are the cause...
PaHu