The support bureau is the group that supports a business. It is the branch office.
If it helps, this word has the same meaning as 支店 which you will also be learning in this level.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
Please go straight to the headquarters in Portland from the Tokyo branch.
Last year, I went to the Tokyo branch of the passport center.
Does TV Tokyo have a Tohoku bureau?