You're a junior but you're taking off a year to apply in your senior year? Do you mean you're taking next year as another junior year and then the year after that is your senior year and you'll be applying?
If you transfer it won't have an impact on getting into medical school. UNT is a great school as is UT. Unless you're on scholarship, I wouldn't take an extra year if you don't have to. The debt just isn't worth it. Now, if you need an extra year for EC's, MCAT, whatever then it is easier to just stay in school an extra year. If you just wanted to take an extra year off before school you could always graduate and try to find a job in Austin and experience the area for a year (I love Austin so I understand the attraction) and work full time.