Help! wireless configuration

Hey guys!

I currently have a modem/router connected to another router by cable, with DHCP off and wireless settings the same as the modem/router in order to expand the wireless range through the house, but the wireless signal upstairs is still weak. So i decided to buy an EnGenius ERB9250 Range Extender to solve this issue, but i cant get it to work, i have tried WPS method and also connecting it manually. the computer connects to the network but it says that the connection is limited and i have no internet access. Please help, i have no idea what i could be doing wrong and i contacted the company and also posted in the forums and got no reply!

thank you