Randy,
Sorry for the delayed response. There's a few questions you're asking here and hopefully I can get you most of the answers you're looking for.
Upgrading
Upgrading JFBConnect should be a simple process:
1) Backup your site, just in case.
2) Download the latest zip file from the My Account -> My Downloads area of this site.
2) Go to the Joomla Installer manager in the admin area. Upload and install the zip file just like any other extension
JFBConnect will automatically upgrade any previous versions as long as you're currently using JFBConnect v4.0 or higher, which is very likely.
Integration
Depending on what version of JFBConnect you're upgrading from and how the integration is currently being done to implement the Facebook button, there's a few different possibilities. In the best case, you won't need to do anything. In the worst, you may need to make a few HTML or Javascript updates. If you can post (or Private Message) the URL of your site where you currently have our Facebook login button, we should be able to get you a better answer.
It'd be best to let us see before you upgrade so we know more about where you're coming from. Also, letting us know what version you're currently using will make it easier to provide some answers as well.
Integration into your existing site is meant to be an easy process though, and we can help you with that.
JomSocial
This, again, depends on your version of JomSocial. Our current integration (I think) works with JomSocial 2.6 or higher. Older versions of JFBConnect worked with earlier versions of JomSocial, so, in the case you're using JomSocial 2.2 (for example) you may need to upgrade JomSocial as well.
The latest releases of JomSocial (v3.0 and higher) actually have integration with JFBConnect built-in. There's an option in the JomSocial settings to enable our integration and, when done, our social login buttons will automatically be added in various areas of their extension.. which makes things even simpler.
I hope that helps get you started, but if you have questions, need more help, or have questions to the above, just let us know.
One last thing.. if you have a development site somewhere, that'd be best. Copy your current site to it.. try to do the integration and take it step by step until you're ready to make it all live. That will make things a lot less stressful when/as you run into issues.
Thanks,
Alex