iMac G3 OS X Update not showing up

Hi, I just purchased an iMac G3 333 Mhz Lime color for $5 at a garage sale with Mac OS 9 installed. I then purchased OS X 10.3.5 Panther retail disk on eBay for $15 and installed it today. The install went fine, except that I try to do software update to get OS X 10.3.9 and other updates for software, but it tells be everything is up to date. Is there anyway to fix?