Did you understand the first reply from RaTTuS and do what he said in his second one? (Put the card with Ultraslim in a B and run the commands, then put the card in your B+.)
Yes I understood the first, but am unable to do the second as the b+ is my first pi
Edit: this probably completely doesn't work but just a though. Could I put UltraSlim on a usb, boot it on my desktop and run the update. Then use win32diskimager to read that image and flash it to the sd?
The problem (not explicitly stated earlier) is that a hardware change between the B and B+ versions has made the B+ USB and LAN chip not work with earlier operating systems, this is why the keyboard wasn't recognized and once updated to the latest version everything should work OK for you.
Takenover83 (who made the Ultraslim) last posted in July and seems to be working on Ultraslim 2.0, so he may not be focusing on fixing the old version to work with the B+ at the moment (But he does still look at the forums, his last visit was on Monday).
Building Management Systems Engineer.