Autumn here, winter approaching
For autumn and winter riding I would recommend looking at some of the kit in the outdoor pursuits industry; much of it works well for biking.
If that old jacket isn't so waterproof anymore, one of the lightweight waterproof tops will fit underneath, so you've still got the crash protection over the top.
I also use a light down-filled shirt that packs down to nothing when stowed, a windproof shell (so thin it adds nothing to bulk) and if it's really cold I have a Primaloft and Pertex hill jacket that also slips easily underneath my cordura kit.
Merino wool base layers are superb for comfort and warmth, and again thin for the layering system, thick merino hiking socks keep the feet snug and warm - the list goes on!