2001 Stratus /transmission issues?

I bought my daughter a 2001 dodge stratus for her 18th birthday the very next day I had to put a catalitic converter on it. Then the next day the car started lunging and serging while stopped at lights with foot on brake. Also started jumping and******** when you put it in reverse, kind of like it didn't want to back up. Then drivng down the road it started surging and almost completely lost power, but I let off the gas and it tried to run right for a minute or then messed up again so I let off the gas again and it reved up all by it's self and felt like it was trying to jump into reverse. Also it sounds like it jumped from drive into neutral because when I mashed the gas a couple times it's almost like im reving it while its out of gear. Im at a loss please help me. My daughter is heart broken she couldn't drive her car to get her license and my car is a straight shift so she can't drive it. So far she has a useless piece of crap for her birthday that she can't enjoy. Im so upset by this please help if you can. Any suggestions?