That site weighs in a little heavy on Pingdom Tools which is odd that page doesn't look that heavy.
Looking at the HTML, there's something really wrong about that output. There's 188 blank lines at the top after a
<font color... line. That may not have anything to do with the slowness though.
Try the usual steps to find the performance issue.
- deactivating all plugins to see if this resolves the problem. If this works, re-activate the plugins one by one until you find the problematic plugin(s).
- switching to the Twenty Eleven theme to rule out any theme-specific problems.
- resetting the plugins folder by FTP or PhpMyAdmin. Sometimes, an apparently inactive plugin can still cause problems.
- re-uploading the wp-admin and wp-includes folders from a fresh download of WordPress.
It could just be a not-so-optimized server configuration too. Give this a read as well.