How to setup a office network with 2 routers and 2 internet connections?

In my office we have 200 PC’s
and 2 internet connections like
1.BeamCable (2MB)
DSL Router – IPCOP Linux Firewall server(192.168.96.4) – switch

2.Airtel (2mb)
DSL Router – Netgear Router(192.168.96.2) – Switch

Netgear Router Enable DHCP (192.168.96.11-230)

But the problem is now we extended system
200PC’s to 350PC’s

now our office setup change to
1.beam cable (8MBPS)
DSL router – DLink Router (192.168.0.2) – DHCP (192.168.0.11-200)

2.Airtel (2MBPS)
DSL Router – NetGear (192.168.1.2) –
DHCP (192.168.1.11-200)

My problem in how to connect to different series of private ip’s (192.168.0.1 – 192.168.1.1) and share internet connection to 350PS’s