Heya,
I don/'t know about any tax experts in germany, but chances are you need to file seperate taxes:
Taxes in canada because of the stuff you made interest in (but I think only if it's over a certain amount) and you probably have to pay taxes in
germany on your german earnings.
Are you working for a company in Germany? They must be able to refer an accountant who can at least help you on the German side.