Source for C02 systems and outdoor planting

1.  Does anyone have any suggestions for a startup systems for a
newbie (to C02 fertilization), e.g.  what to do, makes, (inexpensive)
places to buy them (preferably from the net/mail)

2. I've bought a whiskey barrel and also have an outdoor concrete 
pond (about 3 feet deep). Does anyone have any suggestions for the
kind of aquarium plants that I could plant outdoors to take advantage
of the natural sunlight? My plan is to cultivate/propagate them outdoors
and bring them indoors when the weather turns cold.

Best regards,
Francis Ngoh