Need help with transmission problem

97 Z28, A4 with 125k miles. Car was running well till yesterday on my way home. I stopped to pay the toll and while pulling out (in a normall way, not flooring it) I noticed that the transmission won't shift to the next gear until the RPM reach about 3-3.5K. After that that things appear normal. I reset the PCM but still the same.
I can't repair it myself, but I would like to know what it might be since I don't want to get ripped off by the stealer. Any help is appreciated.

My guess is that it is the servo that applies the #2 band, if it was the band itself it would only do it on high rpm Shifts. Not Too hard, or expensive.