The template overrides Troubleshooting post should help you:
www.sourcecoast.com/extensions/troublesh...ng-joomla-extensions
Basically, the login buttons are contained in that file. There should be divs and other things you can use to make changes in your CSS to hopefully get what you're looking for, but if you need to modify the code, the article above should tell you how to do it. For CSS, to just make the buttons separate, it looks like if you add the following css code to the file below, you should be good to go on that count:
www.christliche-ebooks.de/templates/gk_mystore/css/style1.css
#form-login button {
margin-bottom: 20px;
}
The Login module html code is messy. It's one of the 'oldest' pieces of JFBConnect, and will be getting a minor overhaul soon. This doesn't help you now, I know, but if you run into issues making changes, just let us know and we'll help get you going.
Good luck!