It looks to me as though Avast has blocked the rogue application from downloading.
I'd be fairly interested to see the scan report from SAS, where it found 70 infected files (!), if you can locate and post that, perhaps as an attachment.
Infections found in the location "system volume information" are to do with System Restore. Quarantining something from within renders that restore point inoperable. And sometimes, quarantining is not possible, because the data to be quarantined is too large/locked, in which case it should be deleted.
I think you have done the correct thing, in terms of repeat scans. You may want to turn system restore off, reboot, turn it back on. This will purge all restore points, and new (hopefully clean) points will start to be created. The only reason for doing this is that if there is a trojan in one of the restore points, and you happen to restore using that point, the trojan could gain access to the system. (It's all fairly unlikely, but it could happen, if there were still something undetected in a restore point.)
Dear old faceplant. Problem is that anyone can create a quiz, or a challenge, or something that looks interesting, and the average user is quite likely to use it, unaware that it could be contaminated. There is a "report" button for such applications that are either dangerous, or inappropriate (say, surprise pornography) so that such applications can be reported to Facebook. You might want to use that report button, especially if others (as above) have reported similar problems with a Facebook application.
Of course, there's also always the chance it could be a FP, but unless you really want to use the application, why chance it? The part-URL quoted for the Avast resident protection: "antyspywares.com" indicates it is quite likely to be hosting a rogue. (Try "Googling" that name. Not many hits. (= recent, probably.) The hit that does seem to reference it produces a webshield alert. So I'm inclined to think it wasn't a FP.
I think these social networking sites are a large vector for malware, and that such rogue hostings are likely to increase. Not saying "don't use FB", just "don't go to any old application". Let someone else be the guinea pig.