Difficulties With Join

Hello,
I'm trying to create a report that displays different sized customers in each office.
The tables look something like this:

client(id,size,representative)
representative(id,office)
office(id,name)

I would like the report to look something like this:

_______| all | <10 | 10-100 |
office1|
-----------------------------
office2|
------------------------------

I can get list of the offices and amount of all the clients like this:

SELECT office.name, COUNT(client.id) AS all
FROM office INNER JOIN
representative ON representative.office = office.id INNER JOIN
client ON client.representative = representative.id
group by office.name

But I just can't get my head around how to get rest of the information I want. If anyone has any suggestions how to proceed from here, I would be grateful.