Help me setup 2 IP layer on Belkin Share N300 - Tomato shibby

Hi all !
Please help me setup my network as follows:

ADSL Modem(192.168.2.1)
|
(WAN IP-192.168.2.x) BelkinN300
|
|_ _ _IP Layer A (192.168.1.x-DHCP Lan port 2 & 3 + Wifi1)
|_ _ _IP Layer B (192.168.2.xLan port 1 & 4 + Wifi2)

Many thanks !