It looks like this guide is pretty thorough:
How To Remove Antivirus Live and Other Rogue/Fake Antivirus Malware - the How-To Geek
You'll prolly need to get on another computer to download some of the tools, and have a thumbdrive to save them to, but given both of those you should be able to do it fairly easy. Just print off that guide and follow it step-by-step, hopefully it'll get you taken care of. And maybe on top of getting rid of the Anti-virus Live it'll also get rid of the other stuff that's been plaguing you these past few months