then, select the text tool, and before u do the text part, make sure the setting is set to "create as floating"
then choose ur color nad type in ur text
u should get a text that's selected..then, just simply go to selections-->modify-->expand
and in the box, just choose how thick u want the outline to be.
then just use the Ctrl + C [copy] shortcut to copy the outlined text and go ahead and paste it on ur image!