Inside your rap there are 2 main divs: the content (where the posts go) and the menu. There are a number of ways of solving to position them like you want.
Your content now is:
margin: 0 0 0 0;
I don't know how width 40em is, but I would leave some room for your menu, let's say about 200px. You can do this by changing it to:
Your menu now appears below your post because it hasn't got enough room, and is styled as your rap is (with margin set to auto, which will position it in the middle). So to position it at the right side you can position it 'absolute' or 'float' it (or relative if you had put your menu first in the index file): float:
border-left: 1px dotted #ccc;
border-top: solid 3px #e0e6e0;
If both content and menu don't overlap (which is something strange for me, since adding distances doesn't seem to work always) it will display side by side. If one of the two is displayed beneath, you'll have to narrow them. Also experiment with the padding and see what happens.
Probably you should add a clear to your footer, the paragraph with class credit:
I'm not sure it will work from a paragrap to a div.
ps: not sure whether I can check back for further questions before monday