2000 Honda Accord Celenoids and Motor Mounts!

I am the original owner of this Honda. My mother got into a front end collison about 3 years ago, and had most of the front end replaced(lights, radiator, bumper, fenders) I now have the car and last December the transmission(i believe) starting acting funny. Sometimes it felt like I knocked the shifted into neutral and the RPM's would just rev up but the car would no physically move any futher. Since december I gave a local mechanic $1000 to fix it. He informed me that the car needed new motor mounts and celenoids. He replaced all the celenoids and 2 motor mounts, and the day I picked my car back up, I drove it not even 5 mintues, just for the car to drive the same, if not worse! Sometimes the transmission will jerk real bad and it feels like it kicks into some gear which causes the D4 light on the dash to flash. My manuel says this means a transmisson problem or a miss-fire. So here I am at 21 years old, with no parents, or help from anyone, just a thousand dollars spent that got me NO WHERE! Please let me know if can be of any help! Thank you so much for your time.