I'm pretty sure you've visited their website but just in case. Hiroo Japanese Center
The map on the site is terrible. I've lived in Hiroo for three years, but I couldn't tell where the school was on the map.
Hiroo is a cool place to live; it's in the middle of cities like Shibuya, Roppongi, Ebisu, Aoyama or Shiroganedai where 'Blue Note' is. Living cost is very high in those areas, but then again, it's expesive in most places in Tokyo. A lot of foreigners live in Hiroo from having mansions for people who work at the foreign embassies and consulates, so you will blend right in.
Hiroo is on subway Hibiya line which has many channels to other lines, and there are busses you can take to the stations, so you don't have to live right nearby if you would like to spend less on housing.
I would find a place toward Ebisu or Nakameguro instead of going into the cneter of Tokyo which is more expensive.