How much capacitance do I need in the input of LM78L05
The 33V TVS isn't good enough. Rated reverse standoff voltage is always lower than breakdown voltage. For instance the Littelfuse 1.5KE39A is rated at 33V, but breakdown voltage can be as high as 41V. The LM78L05's absolute maximum input voltage is only 35V. A TVS is still a good idea though, since you're working in an automotive environment. I'll get back to it in a minute.  

Russell suggests using a series resistor, and I concur. The resistor will drop the input voltage and form a low-pass filter with the LM78L05's input capacitor. I would even go a step further, and also place a zener diode on the input, so that you get a shunt pre-regulator. This will cause a little higher current consumption, though, but with a 1k\$\Omega\$ series resistor and a 12V zener this will only be 6mA.
You can then safely use a 1.5KE20A TVS, rated at 17V and with the maximum breakdown voltage of 21V your regulator will be safe.  

Then the capacitors. If TI says a 330nF is required at the input, for pete's sake, put it there! I would also add a 10 to 33\$\mu\$F electrolytic; the zener is a voltage regulator, and all regulated voltages need a buffer capacitor.  

PS: unless the datasheet mentions a minimum dV/dt for the input voltage (it doesn't) there's no upper limit for the input capacitor. Go for that terafarad cap if you feel like it.

further reading
Application Notes for Transient Voltage Suppressors from On Semiconductors.