I think you should give them the proper amount of notice. Especially it they have treated you well during your time working there. I don't know what the job is you are planning on moving to but perhaps that new and better paying job could be used as a negotiation point for more pay at Taco...
She has interest in you. Maybe she is following the advice I'm about to give you. Don't seem overly eager. Don't always call the very next day(sometime is ok). Allow her to believe that occasionally you have other plans, even if you don't. This will cause her to believe there is competition...