All links redirecting to Bing.com

I really hope someone can help me here.

All of a sudden all of the links on my site are directing to bing.com even though when you mouse over them it shows the correct link. My hosts insitially blamed myself and said it was down to malware on my laptop but I have now proved them wrong. They are now saying they think it is caused by a wordpress hack – eval base64_decode Hack and I need to sort it out myself. The do not have a backup of the site so cannot restore it to a clean copy. Does anyone else have any ideas? or does anyone know of a good service that could sort this problem out for me.

Thanks in advance