If your only using it as an AP, try this:
AP mode Router:
http://kb.linksys.com/Linksys/ukp.aspx?vw=1&docid=169333b784cf4c78b8db5490f85c518a_Setting_.xml&pid=80&respid=0&snid=6&dispid=0&cpage=search
http://www.northshore-it.com/tips/how-tos/cascade_linksys/#LAN_to_LAN