Laggy server

Without knowing you machine specs its hard to help you. Start here though.Make sure you have as little running in the background as possible..I disable my antivirus also. Try changing the settings in game to a lower grphics resolution like 800x600. Another thing you can do is get gamebooster. Get it here http://www.iobit.com/gamebooster.html
Run this and defrag the game. Then use it everytime you play. Hope this helps you out.