Looking for a house for a couple and a 10 year old

We arrived in Tokyo a year ago and would like to change to an area closer to Tokyo centre. My husband has a 3 to 5 years contract with a Japanese University so we will be in Tokyo for another 2 to 4 years.
I am French and have started teaching now as I cannot find work in my area of couture design.
Our son is 10, speaks English with his father, French with me and Japanese with Japanese friends. He enjoys piano and drawing ... as well as other activities!
We aim at moving between July and September 2012 and our rental budget is circa 170 000¥ per months; we are looking for a house with garden (to garden in!) or flat with a large terrace; we need 3 bedrooms or 2 bedrooms and study space. We ideally would like a traditional Japanese house to fully appreciate the traditional way of life and culture of Japan while we reside here.