An important question without an easy answer. Your a likely to get a number of varied opinions on what it is that qualifies someone to be an armed self-defense instructor. When you say "armed self-defense instructor" I am assuming your primary goal is to learn to fight with your firearm(s) vs. improve your marksmanship.
Unfortunately, while there are a number of qualified people instructing, there are a greater number of less-than-qualified people instructing as well. The best way to differentiate between the two is to review their resume. Here are the criteria I would look for in an instructor.
1. The instructor runs a "hot range." A hot range is one where the students keep their weapon loaded. A cold range would be one where students load their weapons just prior to firing and unload immediately after firing. Either technique is safe and I believe it speaks volumes about an instructor's qualifications if he is uncomfortable supervising a hot range. Hot ranges and the NRA are generally incompatible.
2. The instructor has instructed for a government agency. If the instructor has served as a firearms instructor for a law enforcement agency or the military it is fair to assume they have the type of background you desire. Most law enforcement/military organization carefully select the personnel they use to train the rest of their personnel. They also often spend a great deal of time furthering their instructors' education.
3. The instructor has completed a nationally-recognized firearms instructor certification program. The NRA runs the only non-governmental firearms instructor programs at a national level that I am aware of. Their civilian firearms instructor program are really geared toward teaching basic skills rather than gunfighting. Their Law Enforcement Firearms Instructor courses are a bit more relevant to what I believe you are looking for in a course. Completion of the FBI's Firearms Instructor Course of the Federal Law Enforcement Training Center's (FLETC) Firearms Instructor Program are two good examples.
4. The instructor has served in a law enforcement or military capacity. The exact capacity needs to be carefully examined. If the military capacity was as a cook on the U.S.S. Minnow or his 5 years in law enforcement was as the motor pool supervisor, your money and time are probably best spent elsewhere.
5. Affiliation with an established shooting school. Most shooting schools are frequented by not only civilians but armed professionals as well. Most schools can ill-afford to have questionable instructors on staff.
6. The instructor has been involved in a gunfight. There is no substitute for experience.
I would say an instructor who has 3 or more of the qualities listed is a good bet.
Some qualities I consider to be "Red Flags":
1. Unwillingness or inability to document military experience. Every person discharged from the military receives a DD-214, even those who served in Special Operations. DD-214's are not classified. If it is not on the DD-214, it did not happen.
2. Service as a Reserve Police Officer. Many less-than-qualified personnel have begun to realize that law enforcement experience is an asset to their resume. As a result they obtain a position as a Reserve Officer in order to claim "law enforcement experience." It is important to note that many qualified instructors also serve as Reserve Officers. The difference lies in whether all of the individual's experience is as a Reserve Officer.
3. Lengthy lists of civilian shooting schools. A number of people take ten courses at school like Gunsite and then feel qualified to teach. While they may have good information to offer, they may not as well. Just as there is a difference between a law school graduate and a law school professor, there is a difference between a Gunsite, Thunder Ranch, etc. graduate and instructor.
4. Over-emphasis on competitive shooting. Lengthy lists of matches attended/won or shooting titles really have no bearing on gunfighting. Some instructors highlight their competitive achievements because many potential students only want to learn from a "Master." Unfortunately, such titles are not awarded outside of competitive shooting. Anyone relying solely on their performance in IDPA, IPSC or another competitive venue to justify their credentials as an instructor is best avoided. If you can attend a class with a qualified instructor who is also a highly skilled competitor (Ernest Langdon and Dave Harrington both come to mind), you are fortunate.
Please keep in mind these are my criteria. There may be some well-qualified instructors who do not meet my criteria.
I am unaware of any instructors in your area. Many times you can coordinate with an instructor to conduct a class in your area. Generally, if you organize a class in your area, you train at a reduced rate or for free.
Below are links to a few instructors I would recommend you contact if you are interested in scheduling a class. I believe Jeff Gonzales, of Trident Concepts, moderates here.
http://www.insightstraining.com/
http://www.internationaltactical.com/
http://www.tridentconcepts.com/