Please Help, Need Help badly

Hello, I recently purchased a 93 accord ex from my sister, anyways, she has owned the car since new and has taken very good care of it. It currently has an unbelievable amound of km on it and is very clean. Several months ago when it was snowing heavily, I was driving and drove into a snowbank because there was a car speeding towards me (it was either kill myself and the other person due to the other guys speed, or drivve into a snow bank and not risk anything like death). Anyways, the car was pretty much suspended on ice, after spending about 2 hours getting it down, everything seemed fine. As it turned out, the muffler somehow had managed to come loose from the engine and was not even attached to the engine for about 1 and half months. I got that fixed, but recently, my D4 light does not turn on, and prior to that, I was noticing that the gas would finish very fast.

I posted the same question on another forum and someone told me that it was my Torque Convertor Solenoid or something like that. If someone could please suggest anything please let me know. I trust the other member on the other board, but I just want to get a basic Idea of where it is and how I can find out if that is the problem really or anyother. I have access to a full garage at school, so is it something I can fix myself? and could it be something else?

Thanks allot for taking the time to read this long and boring post.