Luckily somebody has already done a lot of the hard work for me and create a command line app.
So I added a new APP in the PushOver settings and added the this script to the Pre-queue user script setting in Sabnzbd.
Then I created a Post Processing Script withpathto\myPush.exe /user=YourUserAPI /app=YOURAPPAPIKEY /title=%1 /msg=%1
For Sickbeard I added this insteadpathto\myPush.exe /user=YourUserAPI /app=YOURAPPAPIKEY /title=%3 /msg="Status = %7"
Oh and lastly I disabled the Prowl Settings in SABNZBD. Obviously it'd be neater if Sabnzbd had PushOver support builtin!pathto\myPush.exe /user=YourUserAPI /app=YOURAPPAPIKEY /title="Sabnzb Download Completed Finshed - %3" /msg="Status = %7 %5"