Today I downloaded Sophos Anti- Virus and things seem to be back to normal. So much for an Apple device being free from Virus issues.
That's like saying you sprayed squirrel repellant on your couch, and lo and behold, today you've got no squirrels on your couch! You did not have a virus. See my [Mac Virus guide|http://www.reedcorner.net/guides/macvirus> for information on the current state of Mac malware.
I've heard several complaints about MyWebSearch in the last few days. Evidently, they must have made their web browser toolbar compatible with Safari sometime recently. How it got on your machine, I don't know, but I find no legit indication that it is malware. Sophos lists it as a "controlled application." Evidently, in this case, that just means that it displays (displayed?) ads:
http://www.sophos.com/security/analyses/controlled-applications/mywebsearch.html
Certainly, though, it has been targeted as causing lots of problems, and thus may be the cause of the issue you were having. If Sophos removed it, based on your settings, then that's a good thing.