If you have rebooted since the detection yesterday then the data seen through the avastUI, Network Shield, Last blocked connection won't be available. The network shield doesn't show details as such only that a site was blocked as it is on its malicious sites list. The Web Shield is the one that does a live scan and would say what malware was found.
However, you can check this file using notepad. C:\Documents and Settings\All Users\Application Data\AVAST Software\Avast\report\NetworkShield.txt (XP location) C:\ProgramData\AVAST Software\Avast\report\NetworkShield.txt (Vista, Win7). But as said it is very limited as it isn't like the web shield scan.