How to get rid of the WebRep Firefox extension?

[webrephater]

How can I get rid of the WebRep Firefox extension? This thing got installed without my knowledge and without my consent when I installed Avast on my Mac with OS X 10.8.1.

I think it is nothing but despicable to install such an extension without prior consent and it is even more despicable to install it in a way that it cannot be uninstalled like other extensions. Turns Avast at least in this regard into malware.

By getting rid I mean getting rid and not just disabling. I don't want this thing.

Thanks.

[Jesant13]

I have avast! Free Antivirus installed on my computer which runs Windows 7. I uninstalled the extensions in Firefox and Internet Explorer in the past by clicking the button that says ADDITIONAL PROTECTION, and then clicking on "Browser Protection". I don't know if it will work the same way for you or not though.