Transmission problem 2004 impala don't know what to do? Please read below?

I have a 2004 impala on Friday it stoked shifting until I pulled over and turned the car off and on it's been shifting fine ever since. Now if I take it to a transmission place I have a feeling that no matter what or how minor there gonna just tell me to get a rebuild. My other concearn is that I could get a rebuild and find out it's just a expensive computer issue in the car brain. So my current feeling is to keep driving until it dies completly. I'd rather not get a new car for a year or so. Can anyone offer me any advise?