I shift to drive the car does not Move?

When the car has been sitting for more than three hours or more and the motor is cool, when I shift to drive the car does not move but very slowly if I have high RPMs. Reverse it immediately is fine. Once it changes to 3rd gear after slowly reach that gear. It jolts a little and then 5 minutes later it drives like a charm. No problem. I can stop for an hour and then drive with no issue. I checked the transmission fluid it was low. So, I put some via the dip stick hole. Not sure if that was the place to put it. I was told by a friend to do it that way. Anyways fluid dip stick seems fine, but the problem still persists. I checked the dip stick when hot and it was in normal hot range. But it was very low before. The problem is only when the motor is cold. Once it changes gear to third and runs a little, there is no problem at all. Drives perfect with all gears.