VBA - Selection Box

I have a code (pasted below) that copys a line of data from one workbook into another. Each time i run the code it enters the data on the next available line. This is all working ok however what I would really like to do is when i run the code have it pop up a selection box asking me which sheet i would like to copy from. The reason i need this is that the sheet that gives the data isn't always named the same although the format is exactly the same every time. In this example the data sheet is "copy of NewProductForm), this name may change and i may also have other different active workbooks open at the same time and I don't want the macro to get data from them.

Code :

Sub GetData()
Windows("Copy of NewProductForm.xls").Activate
Rows("48:48").Select
Selection.Copy
Windows("Book2.xls").Activate
NextRow = Range("A65536").End(xlUp).Row + 1
Range("A" & NextRow).Select
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
Windows("Copy of NewProductForm.xls").Activate
Application.CutCopyMode = False
Range("A41:AH41").Select
Windows("Book2.xls").Activate
End Sub