Hello,
I think I can help you but I would like to have some more information.
1- What is the purpose of this configuration? (Im assuming you are trying to add wireless capabilities to your network?).
2- Which router is connected to the modem? How are the two routers connected (from what port to what port?)
3- Lastly, do you really want to have two different subnets? Or is this the only way you found that it could work? If there was a way to have both routers suing the same subnet, would you prefer that or would you like to keep the two different subnets?
Please answer the questions and I will be happy to tell you what needs to be done.