How do i fix my hacked wordpress blog?

My wordpress blog was hacked, when i try to log into wp-admin i get a parse error. I found my wp-login.php using ftp, and it looks like half the code is missing. I am guessing the attacker deleted this to prevent me from logging back in. I tried reinstalling that file with a clean one from a new wordpress download, but now when i try to log in the password field is missing. Any ideas how to clean this mess up.

ps i also found what looks like malicious javascript in header.php

thanks