Unfortunately looking at the IR modules, I don't think you'll be able to do more than 1 per semester, as they only run one 1000 level and 2000 level per semester, and the 2000 level courses require you to have done both 1000 level courses already, and I suspect (although can't confirm) that for 3/4000 level IR modules you need all the 1/2000 level modules.
I think in your sig you say you're doing economics too? You might have more luck here, because you can take the 1000 level courses, but could also take EC2008 Topics in Finance in either semester of first year (it has no pre-requisites), but you would have to find one more non-IR/Economics module to fill the gap in first year. Then in second year, you can take 30 credits worth of Econmics each semester, plus your 20 each semester from IR, giving you a total of 100 credit, so you'd still need to find 20 credits from some other subject.
It can get a bit complicated trying to work out what/when/how many modules you can take!