If you have all the windows updates you are not vulnerable to this exploit, however it doesn't stop sites, etc. trying speculatively to get it past your firewall/AV.
In this case Network Shield has recognised traffic attempting to target that exploit (avast doesn't know you have the relevant patches, etc.), blocked it and warned you... You don't have to do anything else.
The IP might well be in the range for your ISP, but that range includes its users/customers, people like yourself who may have an infected system trying to infect others.
