Actually, the OP is correct. The site has been infected with malware, most probably because it uses/used a vulnerable version of WordPress, which is known for having terrible security vulnerabilities.
If you run it through a malware scanner like this site
you can get some (but not much) more information.
The "3.5~3.5~51.5" is just an encoded script. If you're using an up-to-date browser, it probably can't do much to you, but people with out of date browsers could be in for a nasty shock. It probably exploits a browser bug to download something else... and from there, it can do anything (e.g. steal passwords and banking info).
You're really lucky to have noticed something was up. Someone should probably tell Mr Cosgrove about it.