The car while driving refused to change the gears?

Transmission problem
2002 Honda Civic Automatic 130000 miles

A few days ago, the auto gear shift gave a slight jerk a few times but I ignored it at first. The car went for front shocks change and 5 minutes after it returned, the transmission started acting up (i'm not sure if they are related or if it was the transmission's time anyway).

Problem: The car while driving refused to changed the gear. I stopped the car and a friend (who knows a bit about cars) who was with me checked and came to the conclusion that everything looked fine. I tried to drive but the car just wouldnt move so I shut it down and wondered what to do as it was late and couldnt go to a mechanic. About 10 minutes later, I fired the engaging, put the car in Drive and boom, it started moving but I went slow (5-9 kmph), with care and it drove fine until I stepped on the gas just a little when the car refused to shift and boom, stopped engaging. I had to shut down the engine for another 10 minutes and it started driving again but I kept it under 10Kmph so it would shift.

I got a local mechanic (not very competent) to come over, take a look and he changed the gear oil (his words were that the oil doesnt smell right - there's somethign wrogn with it). Anyway, about 40 minutes later, I started the engine again reversed the car out of my porch but the problem didnt end with infact an addition that when I put the gear in D it gave a strange clanking sound so too scared to cause more damage, I slowly drove back into the porch and parked the car.

I'm getting mixed opinions from different mechanics - some say its the gear box, one said its the clutch plate, etc etc.

From what I've explained, can you be of help and guide me what to do.