Transmission/Computer problem?

2000 C230 Kompressor @ 102000

I started up the car and shifted into reverse and heard a loud clunk. I continued to back out and shifted into drive. When I drove off, I noticed the car would not shift automatically into 2nd, 3rd, or 4th gear. It will just stay in 1st. I pulled over and tried to shift the car into park so I can step outside. I could not shift it to Reverse or Park. Only neutral. And when I shift to Drive, it would be a rough shift. So I went around the block in first gear and went back to my driveway. Put the car in neutral and turned off the car. Then I was able to shift it to Park and take out the key. I started up the car again and the car worked fine. Shifting was smooth and I can go through all the gears just fine. I then left the car for the rest of the day. The next morning, same problems. I shifted into reverse and then drive and it would be a rough shift, then when I tried to shift into reverse or park, I couldn't. I would have to turn the car off in neutral, then I can shift into reverse or park. After several tries of turning the car off/on, it will finally shift fine. I also noticed when the car is not working right, the dashboard would not tell you what gear you are in. It would be blank. When the car is working fine, it would show the gears changing when you shift.

Anybody have any ideas on what the problem could be and how much for the repair. I was thinking of buying a new car now and depending on how much the repair would be will decide on my future purchase. I need a reliable car since I have a baby on the way