My car won't accelerate properly when I shift into drive. What is the problem?

What is your question?

I had my transmission rebuilt and it won't take off into first properly. I have to give it more gas than I did before. When I'm on the highway the tachometer is a little high for driving at 65mph. When I'm parked and shift into drive it doesn't move forward on its own. It drags. It moves forward very hesitantly. What is the problem with my new transmission. This only started after I had it rebuilt. Please help. The shop can't figure it out. Twice already.