If you'd read the tutorial you'd know that kernel.img is what you get after compiling the assembler and C example in it and linking them together. Please read this:
http://wiki.osdev.org/Required_Knowledge
The RPi isn't something you'd want to do if you've never tried writing a kernel for i686. First off the documentation for the RPi hardware is sparse and partially wrong. You'll have to figure almost everything out yourself with little to no help. i686 is very well documented with tons of examples and people who could give advice about it in they're sleep.
That said, you'll have quite some RPi example code here:
https://github.com/dwelch67/raspberrypi
Something to also keep in mind is that models do not all work the same. The memory mapped peripherals might be at a different address. Also the RPi 2B uses a whole different processor. For the RPi 2B you could look at my old code and take what you need:
https://bitbucket.org/nutterts/linloader/src
Edit: If you haven't figured it out in the meantime... rename myos.bin to kernel.img. But trust me, if you can't figure that out by yourself then you shouldn't write a kernel for the RPi. You need to have great problem solving skills.
