Navigation System Software Update

I have a 2004 Solara SLE with the JBL navigation system. I'm trying to find a source for updates to my nav system software so I have updated maps. However, my dealer doesn't seem to know where to get the software. Can anyone point me to a source?

Thanks,
Paul Merideth

well a few months ago toyota send me a letter about changing the software i showed it to the dealership and they ordered it for free, so if theres a better version out there youll get notified