As a Diamond member you have unlimited access to the Tactics Trainer, Chess Mentor and instructional videos as well as hundreds (or thousands?) of articles about all phases of the game for all levels of players. If all this isn't enough to keep you busy for awhile check out my third link, check out the first two for some handy improvement tips.
http://www.chess.com/blog/NimzoRoy/endgame-faqs?_domain=old_blog_host&_parent=old_frontend_blog_view
http://www.chess.com/blog/NimzoRoy/chess-opening-principles?_domain=old_blog_host&_parent=old_frontend_blog_view
http://www.chess.com/blog/NimzoRoy/beginner-chess-book-recommendations
BTW the link you gave is useless, it's only for registered members at chesstempo.
Hello! I am seeking advice for improving my chess game. I joined this site on Sep 2, 2012. I was terrible at chess I started at around 600 rated. I started taking it as a hobby and playing to win, which got me to a 1100. I am now wanting to take it a little more seriously. I have a chesstempo account which I now use regularly. After light reading and tactics I am at a comfortable 1350. I am looking for suggestions on books, programs, sites, and tips. I will link to my chesstempo account.
http://chesstempo.com/chess-statistics.html?r=14#tacticsStats