GW has a fine MPH program. Do you know what funding they have available? Unfortunately, there is typically very little funding available for MPH students. Is going part-time and staying at your job an option? If so, you might want to consider that route. Many of my friends went for their MPH part-time for this reason.
I wouldn't worry as much about the reputation of the school as the courses you take and what you get out of the program. In global health especially, I feel like it's really easy to go through taking interesting content courses instead of learning hard skills. You can always learn the content later, so be sure to take lots of epi and biostats, and probably some monitoring and evaluation courses. Having just gone through many applications to hire someone for a public health position, I can tell you that the name of the school didn't really matter. I was much more concerned with skills. Definitely learn SAS.
So in a nutshell, go to the best school that makes the most financial sense and make sure you get a lot out of the program. It can really be as good as you make it, so take the time to take skills classes, work with professors, and get a great practicum experience. Good luck!