Referring To A Worksheet In A Closed Workbook.

I'm reading data, from specific cells off a closed workbook. When the sheet that needs said cell data is activated, it automatically opens the workbook and references the sheet nessecary. The issue I've come across, is I now need to access another workbook (Easy to open) with 12 sheets 1 for each month, and only read from the worksheet of the actual Month. Kind of lost on how to possibly make this work. I basically need something like: =location/[workbook.xls]worksheet!cell - where worksheet = B12 and B12 =month(today()) and is formatted to MMMM