how do i get more range for my blackberry on my wireless network

I have a blackberry curve 9300 and I am using a cisco valet router to help with cell reception in a mobile home. How can I get more signal strength at the far end of the house without wiring another router at the end of the house. I have looked at other post and people talked about a wireless access point. what and how would i install this type of a device, and is it really wireless (not connected to a router or anything else).