Moving and introducing new cats/kittens - advice please

[iknowimcoming]

We are moving (not imminently so have plenty of time to prepare) to a house with a 1 acre + garden which backs on to forest/wood, road out front is dead end eventually and no one goes more than 20 mph on the stretch near our house (at least that I've seen). I would like another two cats or kittens but we have a small but very feisty/spiteful 11 year old female and I'm worried that she won't take well to them and I've never introduced new cats before. So my questions are would older cats be better than kittens and would it be better to get them before or after we move? I wonder if it will be twice the trauma for my current girl if we move and then get new additions and also wonder if it might help them bond if they all move to a new place together iyswim?