Touch the Dark question

OK I know that I am not really doing this right, don't blame me for saying the wrong book but it wont let me ask for help any other way, but I am really desperate. I need to figure out what a series is called and who it is by, the sooner the better. I only remember bits and peices so bear with me. it is in the paranormal fantasy section, also paranormal romance there is this witch that is i think investigating something. in order to get information and to get magical items and other things to other magical people she uses a demon who is called P.B. but that is not his whole name, just a shortened version of it. this demon is also mentioned in Laura Anne Gilman's Paranormal investigations series. anyway, there is also a whole bunch of paranormal creatures, demons, witches, and a whole lot more. its similar to karen chance, and some of the others. i think it is set in NYC but i am not certain. like i said i have read it a long time ago. and would like to read it again. if any one can help me please please help me i am desperate. i've looked all over the place trying to figure out what this series is called and who writes it. I thank you in advance