Website was hacked. Now have unwanted characters strings of code on Dashboard

Hi,

One of the WordPress websites I manage was recently the victim of a hacking attempt. The site’s Header was changed and unwanted characters were inserted into the pages and posts, into the calendar plugin and finally onto the links that appear on the Dashboard (under the Incoming Links and WordPress Blog sections). I managed to change the Header easily enough, and I got rid of the characters in the site pages by using a Search and Replace plugin. I have e-mailed the plugin developers for assistance with fixing the plugin.

What I need to know now is, is there any way I can fix the feeds on the Dashboard? I tried reinstalling WordPress but that made no difference. I can’t find any settings that seem to suggest they would change anything. Ideally if someone could tell me how the site was hacked or what it fully did then that would be very helpful.

The main thing I want to sort out are the random characters. Here is an example of the two latest entries from the WordPress Blog so you can see for yourself what it is doing:

[ Moderator Note: Please post code or markup snippets between backticks or use the code button. ]

WordPress 3.5 a€?Elvina€? December 11th, 2012
It+ACYAIw-8217+ADs-s the most wonderful time of the year: a new WordPress release is available and chock-full of goodies to delight bloggers and developers alike. We+ACYAIw-8217+ADs-re calling this one +ACYAIw-8220+ADs-Elvin+ACYAIw-8221+ADs in honor of drummer Elvin Jones, who played with John Coltrane in addition to many others. If you+ACYAIw-8217+ADs-ve been around WordPress a while, the most dramatic +AFs. […]

WordPress 3.5 Release Candidate 3 December 4th, 2012
The third release candidate for WordPress 3.5 is now available.??We+ACYAIw-8217+ADs-ve made a number of changes over the last week since RC2 that we can+ACYAIw-8217+ADs-t wait to get into your hands. Hope you+ACYAIw-8217+ADs-re ready to do some testing+ACE Final UI improvements for the new media manager, based on lots of great feedback. Show more information about +AFs...+AF0- […]

Any assistance with this would be greatly appreciated.

Thanks

Ed