Usually, I would suggest Opel GT Source (http://www.opelgtsource.com/) for all of your Opel parts requirements. But mundane stuff such as this should be available from your local Canadian auto parts store. Try AutoValue, or NAPA, and maybe even Canadian Tire.
Canuck Tire probably won't have the Opel on their parts computer, but have them reference the following CT numbers (they are a few years old, but might be cross-referenceable):
Distributor cap: 18-0517-2 (or look for a Bosch cap at AutoValue or NAPA)
Tune up kit (points, condensor and rotor): 18-2675-2 (For better points, look for a Bosch Blue Point set from somewhere other than CT.)
I don't have a reference for an ignition wiring set, but if you take your old set in, you should be able to get a "universal" set, or find another make that fits.
If you are even a BIT serious about having an upgraded ignition system, consider buying an electronic ignitor to replace the points. The most common is the Pertronix (model # 1847V) which should be available from any decent auto store (NOT Canuck Tire!). This fits in exactly the same place as the points, and you should never have to worry about it again. Cost is usually approximately $65 USD from the American supply houses, and I bought mine from the local AutoValue for $110.00 CAD.
As for a coil, you can use any standard non-internal-resistor coil (the stock coil is suplied by a resistor wire) if you are staying with points. I chose a Pertronix Flame Thrower #40511, which has 3 ohms of internal resistance (as required by the Pertronix Ignitor), installed a bypass wire around the resistor wire, and the Pertronix Ignitor. If you want to use a non-resistor coil, leave the resistor in place to supply the coil, but you MUST install a separate switched (i.e. turns on and off with the ignition switch)non-resistor wire to power the Pertronix Ignitor.
Finally, spark plugs. The standard Champion plugs (L-87Y) are OK, but Bosch makes a platinum plug (WR7BP) which are much better.
As an additional note, I went and picked up the Bosch Platinum plugs today from my local Kragen shop, and their computer wouldn't pull up WR7BP, but upon bringing out the Bosch catalog, the model number is now "4232". If you look at the individual plug, the ceramic says 4232, but the metal fitting says the old WR7BP designation.