Wireless Client Mode File Sharring & xBox360 NAT HELP!!!

[kissthis66]

I have searched high and low and just at a lost on what to do as I feel things are starting to go over my head real fast. Here is my set up.

Modem ---wire--- Router A >>> wireless <<< Router B ---wire--- xbox
---wire--- laptop
---wire--- desktop
Linksys WRT110
Router A - IP 192.168.1.1
Subnet 255.255.255.0
Gateway 192.168.1.1
DNS 68.87.76.182
68.87.78.182

Wireless connection to Router B as i can not run a wire across my house

Linksys WRT54G - Firmware Version : v4.30.1, HyperWRT 2.1b1 +tofu13c
Router B - IP 192.168.1.199
Subnet 255.255.255.128
Gateway 192.168.1.199
DNS 192.168.1.199
*** router is set up as auto dhcp, local ip 1.199, sub 255.128, dhcp server enabled, client mode, and set up as gateway)

These are the static IP addresses i would like to have on my devices.
xBox 360 IP 192.168.1.236
Laptop IP 192.168.1.237
Desktop IP 192.168.1.238

Ok so now you know what I am working with. I am able to get the two routers to connect via wifi and am able to get onto the internet with all 3 devices. My problem is i can not figure out how to make the 3 devices communicate with each other. I dont care about being able to share files with devices connected to Router A, i only want the 3 devices connect to Router B to be able to share files.

1. How can i set up my router or devices to communicate with each other so they can share files?

2. When i set a static IP to my xBox360 i get a strict NAT error, but when i have it set to automatic it does not get an error message. why is that and how can i fix that?

Please and thank you all for taking the time to help me out! =)