Hi Helen,
I carry all manner of things to cover every eventuality (well almost) Most breakdowns are not going to be fixable by the AA/RAC apart from the easy things like Generator belts or flat batteries.
I would suggest at least the following which will help either you or the Breakdown person to enable you to get on your way, anything more serious will need a trailer home:
Generator belt and Spanner
Pulley halves
Oil
Bulbs
Jacking plate (assuming your jacking points are sound)
Decent scissor jack (not the supplied Porsche one)
Spark plugs
Selection of spanners/screwdrivers etc.
Cable ties
Jump leads
Warning triangle
Petrol can
If you are feeling more competant:
Points
HT Leads
Coil
Distributor Cap
Regulator
Fuel filter
Clutch Cable
Feeler guages
I'm sure I have forgotten something but you get the idea...