If you are not using a router, then open a command prompt window and type ipconfig. The line titled IP Address will list yours.
If you have a router, you will have to access it's settings & look the IP address up there. See it's manual or website for details.
BTs stats list kBytes not bits. So, for example, my download speed for a file piece at the moment is 6kB/s. 6 X 8 = 48kbps, so for your 15kBps download you are actually getting 120kbps. (Not talking down to you, I just don't know how much you understand of bits & Bytes
) The more pieces you can get at once, the faster it will become.
Download speed will also be limited by the upload speed of whoever you are getting the file pieces from.
Hope this helps!