interesting morning

so.... i just got back from a 20 minute run to chemist.... pulled on to drive with windows down and i hear a clunk and charge light comes on..... me thinking that was loud for a belt snapping. popped the hood and yes belt lying on bottom engine cover ... along with the crank pulley! bugger! anyone know what size the bolts are to get the hub off will this be a hub puller job? i ordered a new pulley....bang goes a few evenings down the pub 2013 A8 CDTA 3.0 any hints and tips would be appreciated. Once the hub is off how big of a job is changing the front seal as i think that is leaking too.
thanks in advance