Church service can be brief (20minutes?) but a lot depends on choice of hymns, prayers and readings, any if which can extend it greatly, as can lengthy or numerous addresses and tributes. Is there to be an interment at the church, or will there be a crematorium service too?
Hope you are ok fridge. My not very helpful answer is that it depends - but I would have thought you should allow to 2.15 for the service - may be shorter, may even be slightly longer - up to an hour and a half. As for the reception, it may go on for the rest of the afternoon, but with people leaving as and when - or it may end fairly early if the family are going on to the crematorium alone later for a burial/committal. Sorry, this is not very specific! - but I think it does vary a lot. You could phone the funeral directors to ask if they have more details?