DD-WRT Client bridge on Linksys E3000.

These steps are adapted from http://www.dd-wrt.com/wiki/index.php/Client_Bridged. However following those steps exactly did not work for me. So I modified the steps.

My Access point router IP address was 192.168.1.254 (not a DD-WRT router) and E3000 router IP address was 192.168.1.1.

1. Download and install a recommended build for your router. DO NOT USE SP1. I used Kong build 19200M (SP2 build).
2. Do a HARD reset on your router (press the reset buttom on the back of E3000 router for at least 15 seconds).
3. Connect a cable from your computer to the LAN port on your router.
4. Set your computer to a static IP address of 192.168.1.9
5. Set your browser to 192.168.1.1 and open the dd-wrt webgui.
6. You should be asked to change your password and username. Carefully type these in. (If you aren't asked for a password and username, do a hard reset, this time doing it properly!) Hit change password.
7. Go FIRST to wireless, wireless security and enter the security type and key that matches your primary router.
8. Hit SAVE, (NOT APPLY)
9. Go to the wireless, basic settings page and change the wireless mode to Client Bridge.
10. Your wireless network mode, channel and encryption should be set to the same as the primary router.
11. Set the wireless network name to exactly the same as your primary router. Make sure spelling and capitalization match.
12. Hit SAVE, (NOT APPLY)
13. Goto Setup, basic setup and enter a router Local IP address of 192.168.1.1. (it will be already that IP address). Leave subnet mask at 255.255.255.0.
14. Set the Gateway IP to the IP of your primary router. (192.168.1.254 in my case)
15. Leave Local DNS blank
16. Change your timezone and DST to match where you are.
17. Hit SAVE, (NOT APPLY)
18. Goto Security, Firewall. 
19. Disable SPI Firewall
20. Hit Save and then Apply.
21. You are done. Wait for at least 5 minutes for the router to apply the configuration and get the internet connection from primary router.