Iron Shipwright makes a 1:350 scale resin & brass Halifax-class FFH
As mentioned above, The Resin Shipyard makes several Canadian Navy subjects in both 1:350 scale and 1:700 scale.
http://www.resinshipyard.com/pages/catalog.html
Their 1:700 scale Halifax is very nice, but the photoetched masting might be intimidating for a first-timer. If you don't want to do the whole ship, you can get just the 57mm Bofors gun in 1:72 scale. Check with Darren at RS, they may now come with decals for gun 'nose art'.
Darren at RS also sells Colourcoat brand Canadian Gray/Green paint, made specially for him by White Ensign Models. Their photo CD walkaround of the Halifax FFH is nice for getting the details right