SunCross from what you where told by the people who pulled the codes about getting a new transmission I would NOT LET THEM work on your car. They are not giving you good info; Do not trust them.The codes are P0715 Input/turbine speed sensor, P220 Input Sensor mismatch, P2203 N3 Input speed sensor circuit, P2300 Bus-off CAN Controller 1, P2500 improper gear ratio. To me those all point at the conductor plate as the speed sensors are on the conductor plate. At this time I would only clear codes and see if that will get you out of limp mode. If the codes clear you are good to go. If they reset you will need to replace the conductor plate. FCPEuro has a kit with the correct fluid (Pentosin ATF134) for about $275. If you need to replace the conductor plate ( It can be done for a skilled doer your seilfer) I would take it to a different shop than the one that pulled the codes for you. Please go back and read my previous post and answer those questions with only 35.000 miles on the car it shouldn't require a transmission fluid change in respect to regular maintenance.

PS what pizza guy suggested about looking under the passenger floor mates to check for moisture you should already have done. That is the consequence of the plugged drain lines. The transmission control module is located there near the radio amplifier.