Suspension/Transmission

I have a 2000 Tiburon. I know they didn't come from the factory with the cushiest suspension. Whenever I hit the smallest bump It feels and sounds horrible. Any suggestions on what exactly needs to be repalced?

Sometimes my trans will jerk and make a hollow clunking noise. It also will get stuck or drop down to a lower gear and It won't shift past the gear that it's stuck on.??? By the way, It's an automatic.

Thanks in advance for any advice on either question. It will be greatly appreciated.