Google Reader Translate is a Firefox add-on that adds a translation feature to Google Reader. It won't translate full feeds for you (that would probably take forever), but it does translate every headline in a given feed. Click on the article and it will open up in a new window using Google Translate.
Unfortunately, while Google Reader Translate converts any language covered by Google Translate to English, Slovak isn't one of them. And that's the language the article describing this Firefox add-on is written in. It's not too hard to find the download link though. Just scroll through the page until you find the text "je možné inštalovať tu (XPI súbor)"
In order to translate a feed, you'll need to rename it in Google Reader, placing a three character preface before the title. For example, if you want to translate German to English, you would name the feed .de [feed title]. For Spanish, you would use .es [feed title].
[Thanks Patrick!]