Which do you need, a cordless drill or impact driver? Of course you need both, at least I do. If you've never tried an impact driver take the time to do so, and time to stand in the checkout line once you decide to buy it.
How to use a power drill. There is corded and cordless I personally like the corded variety because I have owned 1 of those and have owned about 3 rechargeable drills, the rechargeable drill simply don't stand the test of time. Also purchase a set of drill bits and don't forget to purchase a drill bit for driving screws in, very important option. Every woman should own and figure out how to use these, they are terrific!