Need Internet connection on Raspberry pi with Piratebox running Simultaneously

Hi,
I have configured the piratebox on Raspberry Pi and using it by the Wifi adapter,
but I need internet connection to raspberry pi through Ethernet port and also simultaneously don't want to disturb Piratebox Configuration. so please tell me the essential network configuration to achieve it similar to this thread on TPLINK MR 3020 on Openwrt [forum.daviddarts.com]

my /etc/network/interfaces file looks like

auto lo

iface lo inet loopback
iface eth0 inet dhcp

#allow-hotplug wlan0
iface wlan0 inet manual
#wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
#iface default inet dhcp

and my ifconfig output is

eth0      Link encap:Ethernet  HWaddr b8:27:eb:75:94:94  
          inet addr:192.168.9.123  Bcast:192.168.9.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:26018 errors:0 dropped:0 overruns:0 frame:0
          TX packets:170 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:1490865 (1.4 MiB)  TX bytes:13093 (12.7 KiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:49 errors:0 dropped:0 overruns:0 frame:0
          TX packets:49 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:5368 (5.2 KiB)  TX bytes:5368 (5.2 KiB)

mon.wlan0 Link encap:UNSPEC  HWaddr E8-4E-06-14-9E-01-00-00-00-00-00-00-00-00-00-00  
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:4236 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:1405407 (1.3 MiB)  TX bytes:0 (0.0 B)

wlan0     Link encap:Ethernet  HWaddr e8:4e:06:14:9e:01  
          inet addr:192.168.77.1  Bcast:192.168.77.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1602 errors:0 dropped:36 overruns:0 frame:0
          TX packets:1252 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:202095 (197.3 KiB)  TX bytes:343586 (335.5 KiB)

please tell me detail how to to run Wan on Raspberry Pi without disturbing Piratebox.

Thanks in Advance