Those login buttons from JFBConnect are actually added by JomSocial when you enable the "Integrate with JFBC" setting in their Facebook Connect settings area.
I'd recommend contacting them and letting them know that it'd be great if there was a setting to alter the position.
In the meantime, you can take a look at our
JomSocial Integration guide
. The steps in the JomSocial 2.8 section still apply to JomSocial 3.x. The files to edit are shown there, and you should be able to add the {JFBCLogin} tag to a higher portion in that file.
Another note is that you can use the tag like the following:
{JFBCLogin text=Register with}
That will append some text before the login buttons. Otherwise, since you're editing their template file anyway, you can add whatever description you want before the tag.
I hope that helps!
Alex