powershell: get scep status from sccm 2012 (sql? )

Hi,

I would like to query (via powershell)sccm or sql behind sccm the overall health of antivirus in a domain.
F.e.: 90 percent of clients have recent virus update (definition xyz), y number has definition older then a week,z pcs are infected etc.

The data is there in sccm and reportingserver but how can I retrieve this via Powershell?
Goal is to present this in a simple kpi dashboard, together with other figures.
Really prefer Powershell since it is most flexible vs Sql report of which my knowledge is basic.

Thanks!

J.