Yikes! I'm glad that besides the ear infection, it sounds like the puppy is just fine.
I lived in Nashville for a few years and used to take my kitty to Pet Med
PetMed - High Quality Veterinary Medicine (Antioch, Tennessee). They are located on the east side of Nashville, only about 20 minutes away from Murfreesboro. I don't know if they offer emergency services, but it is an excellent vet clinic. My younger sister volunteered there over a summer or two and said everything that goes on "behind the scenes" is as kind and ethical as the public image/reputation that they maintain.
That said, Murfressboro is an absolutely booming town now due to the university and housing prices skyrocketing in Nashville ... I'm sure she can find an excellent vet right down the street!
I'm sorry your niece is feeling lonely ... I just moved to PA for grad school and got my little yorkie a couple months ago ... he is a ton of company for me and is such a comfort! I really don't know what I'd do without him. I think your niece's pup will really be a blessing for her.