You can see the Pop-up Login Module on the very right of the screen --->
You can publish the module "On All Pages" and it will always appear there.

BT Login Module

• Ability to run the same time with login module of Joomla
• 2 style display options : Modal box and Drop down
• Allow to load other modules
• Log-in/Log-out Redirection Page options
• Ajax Login & Ajax Registration
• Support Recaptcha
• Support to open login/registration popup anywhere with click event
• Integrated component: K2, JoomSocial, CB & Custom
• Easy and friendly back-end administration