When introducing formula, the best way is to try to use expressed breastmilk and add half an ounce of formula to it, increasing the amount of formula over a week or so. Sometimes it isn't the bottle that the baby rejects but the taste of the formula. By slowly increasing the ratio of formula to breastmilk you allow the baby to get used to the taste gradually.
In order to avoid problems with supply, it is usually recommended to breastfeed only for the first three weeks and then begin expressing/introducing formula.
And there's very little difference in how much sleep breastfed v formula fed babies get. In fact recent studies suggest that breastfeeding mums get more sleep than formula feeding ones. At the moment my little man is teething so no one in the whole village is getting any sleep, but boob is the one thing that can knock him out!