conor_mc, I flew from Dublin to NY with Aer Lingus (EI) for €340 and then on to Winnipeg with Air Canada, via Toronto, for US$327. I went through NY as I wanted to spend a couple days with my Brother who lives there. Unfortunately though, you can't fly direct from NY to Winnipeg. Might be easier to fly via Chicago with EI and then direct to YWG with AC or one of the US carriers. EI do some good online deals if you book enough in advance. I know Air Canada used to fly from Dublin to Toronto but don't appear to anymore. Might just have been a summer season thing.
You can check out the Harv's Air rates here
http://www.harvsair.com/site/information/rates.html
YYZ, how's the hour building going?