I don't go to UWO (I go to U of Manitoba), but our dues are not outrageous. However, none of the chapters here have houses to pay for. I don't know if there are houses at UWO, that would be a question for the chapters there. Our chapters' Panhellenic dues range from $550-650, fwiw. A certain amount of dues has to go to Internationals, and then your chapter has operating costs. You can email your Greek life office, or if you don't have one, your Panhellenic and at the very least get a range of dues. Anoter question- are your parents going to be paying your dues? I've personally felt like I've gotten more than my moneys worth. Going through recruitment, each chapter should have a basic breakdown of your dues. Also, once you join a chapter, you should be able to ask your VP Finance for an in depth breakdown. I would recommend making a list of questions and either a) emailing Panhellenic, b) emailing all of the chapters, or c) both (I emailed Panhellenic and all three chapters in the summer, they all answered my questions).
ETA: The UWO Panhellenic website isn't up right now, and I'm feeling bored, so here are the 5 chapters' websites:
Alpha Gamma Delta:
http://www.agdwestern.com/ (The AGD website is under construction but there's a contact email at the top).
Alpha Omicron Pi:
http://www.aoiiwestern.com/index.php
Alpha Phi:
http://www.alphaphiuwo.com/
Kappa Alpha Theta:
http://uwotheta.blogspot.com/
Pi Beta Phi:
http://www.pibetaphi.org/pibetaphi/uwo/
Also, Ontario's system can be a little confusing (looking in from other provinces, at least). There's info on (I think) all of Ontario's Panhellenic groups on the Toronto Area Alumnae Panhellenic website. Hopefully this can help you out!