Here's what you do:
1. I assume you haven't done anything with the Cisco router and it has been working this whole time. By the looks of your drawing though, your laptop doesn't seem to be able to communicate with the Cisco router. iI believe its because your Cisco router is not issuing DHCP, but in fact you have to statically assign computers (and wireless routers
) with ip addresses. Go to the front computer that does work, and open command prompt and enter ipconfig /all and write down all the info. You need this info for step 5. And while you have the command prompt open ... ping an address that is likely to NOT be in use. I.E. if the front pc's ip address is 10.1.1.5, then try pinging 10.1.1.6. If you get 4 "request timed - out's" then it's probably safe to say that is an address you can use later to assign to the Linksys wireless router in step 5.
2. Reset the Linksys wireless router to factory defaults.
3. From the Cisco router select a LAN port, run an ethernet cable to a LAN port on the Linksys Wireless router ... NOT THE INTERNET PORT. Yes ... you read that right ... not the internet port.
***Think of your Linksys wireless router as another computer on the network and it's only job is to pass/forward DHCP requests between the Cisco router and other computers that connect wirelessly. So Linksys Wireless router has to use a LAN port ... like a regular computer.***
4. Take your laptop and using another ethernet cable, plug into a different LAN port on the Linksys wireless router. Allow your laptop to receive its IP address automatically via DHCP from the Linksys wireless router ... for now. You may need to right click on the network connection and do a repair in order to renew your ip configuration. Or you can do an ipconfig /release, then ipconfig /renew. After you're up again, do another ipconfig /all and write this info down. You'll need this for steps 5 & 10.
5. Log into the Linksys wireless router (192.168.0.1 or 192.168.1.1 - the default gateway from the info you gathered in step 4.) In basic setup, set your WAN address to static ip (its defaulted to receive dynamically) and assign it a static ip address from the subnet of your Cisco router. ***Here is where you would use 10.1.1.6, if that is the address you found NOT in use from step 1) Put in the subnet mask and default gateway that the Cisco router uses as well (you gathered this info earlier when you had your laptop plugged into the Cisco router and did ipconfig /all).
6. Continuing in basic setup, turn off DHCP. Don't worry, you will still be able to continue configuring the wireless router until you exit setup. I'll explain later how to log back into the router after we're done.
7. Most linksys wireless routers have an Advanced Setup area as well. Here is where you will tell it to be a "router" not a "gateway". I know ... this is ass-backwards, but that is how it is supposed to be in order to turn the wireless router into an access point and allow the Cisco router to issue DHCP through to computers via wireless.
8. Configure your wireless security ... WEP, WPA or whatever you choose.
9. You're done.
10. Now in order to log back into the Linksys wireless router at a later time, all you have to do is manually assign your Local Area Connection of your laptop an ip address from the subnet of the LAN configuration of the Linksys wireless router. If you wrote down the ipconfig info I told you to in step 4, just put in the info from that and you should be golden. The reason you have to do this is because you turned off DHCP of the wireless router ... however the LAN subnet is still there ... you just have to put your laptop back on that subnet. Understand?
I know this is a lot of info and could seem overwhelming ... but if you take the time and read each step carefully and follow them, you're going to look like a genius to your boss.
Good luck ... hope this helped.