sleep schedule

My one year old sleep is so off . She sometimes doesn't go to sleep till 11 or 12 at night . Even going to bed that late she still manages to wake up throughout the night . She only takes 1 nap a day . Sometimes for for 30 minutes , no more than a two hour one . I have another baby due in two weeks and I'm already sleep deprived & it's not going to get easier when the baby is here . What are some suggestions