This should have been resolved by updating the virus definitions (which was available fairly soon after it became known), ensure that you update the virus definitions.
Any other action require on what actions you had avast set to do ?
For the most part, never set avast up to delete as a first choice (I don't set it for any choice) as you have no choices left. Always make regular (weekly) backups of your system, to help recovery from any issue not just an FP.
As for getting another antivirus isn't going to help you with this and I don't believe there is an AV that hasn't has an FP and some have been much worse than this.