Hi,
I have a 2003 model with 86,000 miles (approx 137K km), in summer I get high 30's mpg and (around 14km/l) and on long runs and fairly loaded, can do even better. Winter is low 30's mpg (say 11 km/l), but we do not have anything like your cold winters in SE England! I do drive fairly sedately (not that there is any choice!), but am happy to exceed 60mph on motorways when I can still maintain good fuel economy. It does hold 3 bars most of the time and on rare occasions reaches 4 bars. There are companies in the UK that can replace individual failed cells in the hybrid battery, which is a far cheaper option than full replacement. Interestingly the company I found advertised on Ebay and were of the opinion my battery was fine (thankfully!). You may find companies offering similar services in Canada, if the suggestions already made do not work for you. Good Luck.