Congratulations!
Traveling between Toronto and Ottawa
VIA rail Canada (http://www.viarail.ca/en) is a good way to travel.. and they are offering a 50% discount now. Rail travel can be very relaxing.
There are frequent bus services operating between the two cities - some of the fares appear to be rather within the range of 50 CA$, one way. http://www.greyhound.ca/ticketcenter/en/Step4.asp
You may also catch a ride share with someone driving to Ottawa on the day you wish to travel. Some drivers do offer a lift for a small charge. http://toronto.craigslist.ca/rid/
As for temporary accommodation in Toronto, your question can be better dealt with if you can provide little more information: e.g. what you wish to do during your stay, the places you would to wish to visit, whether you would want to visit friends or family you may have in Toronto and where they live, your budget, your preference for the type of accommodation e.g. Luxury hotels (http://www.hotels.com/), furnished apartments (keep an eye on posts on Craigslist and http://toronto.kijiji.ca/), short stay hotels and so on.
Wish you a nice trip to Canada.
// O