Networking help again

[boybi]

This is my setup at my home and office:

DSL Modem---Wifi Router 1---[LAN cable]---Wifi Router 2---<wirelessly bridged to>---Wifi Router 3---[LAN cables]---Office computers & server

Blue = Home
Red = Office

Routers 2 & 3 serve as access points/hubs
Router 1 assigns the IP addresses.

Here's my problem:

There are times the power cord for the Router 2 gets unplugged accidentally, so the office side will lose internet connection. If the computers in the office are turned on before the Router 2 is unplugged, they can still access the server since they've already been assigned their respective IP addresses.

But if Router 2 was unplugged before the office computers were turned on, then none of the office computers get to access the server.

What I like to know is, can the office side have it's own DHCP separate from the home side? I mean, I want the office and home to have their own separate networks, but the office side still get its internet connection from my home network. Is this possible?

If I can do this, can the office computers still have access to files stored on my home computers?