You can download official firmwares for your drive from http://us.lgservice.com/index_b2c.jsp
Click on Device Driver and then on DVD-ROM/Writer which will take you to a page where all the new firmware releases are posted. Afetr a quick look I see the latest version for your GSA-4163B is version A103.
Often you can also download firmwares off unofficial sites but you have to be careful with these. When flashing your drive with an unofficial firmware version you may void your warranty. Firmware releases can be "hacked" by people, adding better media support or, for instance, removing region locks from your drive. You should experiment with unofficial firmware version at your own risk.
Hope this answers your question, welcome to the forums