I would shorten the day sleep and make sure she falls asleep early in the day (for her nap)
Make the wind down to bed longer (ours starts at 5pm for a 7 pm bedtime with dinner and then bath and then quiet play like blocks or drawing)
Sit or the end of the bed so dd can't be too distracted by you or lie down with her and pretend to go to sleep (my dd won't let me leave the room even at three)

Otherwise does she have her two year old molars? Could she be getting them?

Does she go to day care? Do you have any friends or relatives who can come and play with her in the arvo?
The other major change in her life might be just that you a home more because you have a new baby, so she's not getting tired out enough. I don't think you should rush around and try and change that yourself, but if dh took her to the park before dinner or something it might just get rid of some of that energy.

Good luck! It's frustrating when you have to sit in the dark for ages. I always take my iPhone and read bb or the news, so that helps a bit.