Where can I change the the login text?

The strings for the JFBCLogin module should all be in the
/languages/en_GB/en_GB.mod_jfbclogin.ini file

You should simply have to change the text on the right-hand side of the equal (=) sign to whatever you want displayed.

The reason the button is above the module is because of the absolute CSS statement below:
www.reviewbahrain.com/templates/rt_quant...j15/css/template.css

a.fb_button.fb_button_medium {
height: 22px;
position: absolute;
top: 0px;
left: 16px;
}

If I remove the position:absolute attribute, the Login button shows up under the form (where I would expect it). You may still want to put some margin on it to space things out a little more.

Hope this helps!