Hi, my son is in 4th grade. In 3rd grade we put him in a private school shortly after we had him take the WISC-IV test. It's not a gifted school, but the classes are small and they are less rigid than his public school was.
We get a good deal of financial aid towards his school. In fact we declined their first offer because it still cost too much and they brought it down again.
PM me if you'd like to talk more.