Hi Kiss congrats on getting your new addition to the family 
I didn't get a carrier for the car so can't advice on what is best, I just bought a car lead like this have used it for the first time today and it was fine.
Apart from the usual which I am sure you know, lead, bowls, toys etc, I also got a an extendable lead, I use puppy pads as am out for a few hours at work during the day, some people like them, some not, it works for me, and she only uses one of them now which is right by the back door so signs are good for her wanting to go out.
When we picked her up, we took a blanket and rubbed it on her brothers and sisters, and that really helped on the first few nights to settle her and she still sleeps with it.
Will have a think and see if I can think of anything else, but there is a font of knowledge on here much more experienced than me 