This is a trojan/backdoor usually installed using a rootkit. It's potentially serious, depending on the particular version, which I am not eductaed enough to deduce.
One of it's assigned names is "banker trojan", another includes the title "infostealer", so it would be in your interests to change any passwords, especially to banking sites.
Check your AVG quarantine, also the firewall log of blocked connections. It is likely (hopefully) that the firewall should have prevented this thing from connecting outbound, unless you approved it.
I'd also run a disk cleanup using
ATF Cleaner (This one runs from the folder it is downloaded to; no install required.) Tick everything except "cookies" and "history" and run it by clicking "empty selected.
MBAM is usually pretty good at this sort of thing.
Reboot, update MBAM, run another quick scan, if anything malicious found, please post back.