Sorry you are having a hard time, but there are two clear reasons & both can be fixed (with hard & consistenet effort on your part)
Firstly you need to work on extending the 45min naps as she can't resettle herself to sleep... I suggest looking at the nap forum for that there are some great announcements on how people have dealt with it (One by Deb is very good). 45min naps are very often the cause of night waking. At 15weeks you should give your daughter 2- 3 solid naps of about 2 hours each (+ a cat nap, if she only takes 2 long ones) Over tired babies are also prone to wake up more at night.
Secondly I think the dummy is also a problem, she doesn't know how to go to sleep/back to sleep without it, so it is probably time to wean her from that too. The props board also has great announcments on how to do that.