I've been stumped as to how I should code this menu in html/css. The fact that the text is right aligned, and the placement of the button background throws me off.

Can anyone help me out/guide me in the right direction?

Do you have any experience with HTML and CSS?
If so a DIV with the dark background is needed and inside of it a second one with the rounded corners background image - I'll called it "menu". Inside the menu place an unordered HTML with absolute CSS positioning in order this bent-effect of the buttons to be placed exactly at the end of the menu as your attachment shows!!! The list's bullets background image should be this green or whatever bent-effect image with alpha-transparency and in anchors place the links' text.
If you have any particular question, don't hesitate, shoot!!!