by january do you mean july?
Shouldn't be too hard to find somewhere to rent at that time of year, probably your best option would be to budget staying at a backpackers / hostel for 2 or 3 weeks when you arrive. That way you can get a feel for the place and find somewhere to rent.
Usually someone will take a lease out on a house and then advertise for flatmates for the left over rooms. You could probably expect to pay something between 100-200 depending on number of people and quality of house etc. Obviously you could spend more if you wanted or possibly less if you're sharing rooms with other people.
is a good place to get a feel for what the rental market is like - http://tinyurl.com/wanakarentals