RSS spam appearing in google reader/ technorati

Hi, my website https://www.alexcf.com/blog has been infected with spam, google reader and technorati show spam instead of my post, it only appears to affect a few RSS readers, but its driving me mad constantly being reminded that i have a problem. I tried using exploit scanner, and it produced this:

Modified Core Files

1. The file containing the checksums of all the core WordPress files appears to be missing. Either you have upgraded WordPress and this plugin hasn’t been updated with the new hashes or the file has been deleted/renamed. You will find that a lot more files have been returned in the Suspicious Strings section.

if anyone knows how i could deal with this, or how to remove this problem i would greatly appreciate it!

thanks
alex
(using my partners login)