I feel sorry for you people with automatic transmissions - your symptoms come up a lot.

Bad news: Ya got trouble, and it's gonna cost you to fix it.
Good news: You do not need a new transmission - you need someone who knows what they are talking about! (That's not me, my only answer is "Sell the damn car and get one with a manual"; but wait a bit and you will get the information you need.) I"m betting a fluid flush, refill, new conductor plate and maybe new o-ring/electrical connector and you will be good to go.

On the other hand, you have a throttle position sensor code..... And I'd pull the floor mats up on the passenger side and look for water intrusion under the plate that hides the TCM and audio amp.