My undergrad cumulative GPA was pretty bad as well... All thanks to three and a half years in a highly competitive engineering program before getting much better grades in linguistics for a BA. I was encouraged to get a master's before considering a PhD and ended up at Northeastern Illinois. They have a great linguistics program (you definitely get the background plus all the profs work in applied subfields) and a big TESL program as well. You might want to check them out and send the professors an email with questions. They also accept new students at each term, so you have some flexibility with application timing.