hi aredfern! welcome to the
club! you can use the forum's search function to see if any members have this issue or you can check for a response as a members in this club are quite knowledgeable.
how about letting us know what i30 you have, the make & model of your car stereo, if it's an aftermarket unit (as you mentioned that you want the gps to talk through your stereo) & maybe how you are connecting your ipod (are you using a Hyundai ipod cable or just the normal ipod usb cable)
i ordered a Hyundai ipod cable from ebay but found that the normal ipod usb cable works fine ... waste of $13
only thing with the normal usb cable is that control of ipod (song search) is transferred to the stereo but that's with the car's stock stereo unit