Can I recommend another great book which has sleeping logs for her to record nap times etc, and gauge patterns...'The No Cry Sleep Solution'.
Really helpful, especially with help in getting your baby down for their nightime sleep earlier, which is probably the area she needs to assistance with.
'Most' babies crave an early bedtime, which research has shown actually helps a baby sleep longer.

On an average day at 3 months Paige will sleep from 7-8pm, until 7-8am with one or two wakings in the night.

I believe the key is in setting nighttime rituals/routines, that cue a baby into learning that sleep time is approaching. We begin ours at 6pm every night.

During the day Paige will nap from 40min to an hour roughly around:
9am
11am
3pm
5pm

BUT I really do just look for her tired signs and not the clock.

I do recommend the book highly for lots of advice on setting up nighttime routines etc...again, there are logs provided to record all this stuff.