Transmission problem

Hi, everybody,
I bought an A8 4D2 11/98 last week, mileage 214,000km,
I have now driven about 1000km and now I have the following problem of the A8 jumps on also drives backwards and if I put the selector lever on D he drives off and then there is a jerk and all the lamps of the gear indicator shine on I then have to give a little more gas that he comes from the stain at all. What can that be?
Thank you in advance M. Klapper