car wont shift into the right gear, tried going faster than 15mph but rpm gauge went all the way up to 3 and kept on going up. went to see what the problem was and the guy at my local parts store did the computer test and said it could be the speed sensor in the transmission. Now the car just doesnt move. Put into reverse souds like it went into gear, but when I pressed the gas the car wouldn't move. Same thing happened when I put it into drive. The car is an automatic. Don't know if it is the sensor or the actual transmission. I'm a single mother of 3 and I need someones help with the problem.