I am almost certain Civics have a MAP and not a MAF, it should work but will need a little tweaking of a value. Your car should talk CAN yes.
You can buy the OBD-II to serial cable here
OBD Diagnostics, Inc. - OBD2 Cable
Radio-Shack will not have it, it's hard to find in store, it's better to buy it online.
If you have a serial port on your PC/laptop, you can buy a assembled maxserial for less than $20 at Fundamental Logic webstore.
For all the others components, I know digikey in the USA is a good online supplier.
For the ELM interface, note that C5 and C6 are monolithic, the others are standard ceramic. For C3 and C4, the value depends on the crystal, it's written on it and in the description on digikey webstore for instance.
EDIT: you can buy the ELM327 only on their web site:
http://www.elmelectronics.com/