G or N Wireless Expander

Help with the following.

I have a Belkin connected at the Main House and a Linksys G Expander at opposite side of the house in a window and the garage is about 350 to 400 feet away with another Linksys expander in the window and you can see both indicator lights on both expanders when you are at the window in line of site.

Is there a way to improve the reception better, It is still slow at the garage due to (2) expanders and the Belkin at the DSL.

The Belkin is not easy to move in a different location due to were the main computer is and thecable comes into the house at that location.

I am using the following equipment

1. (1) Belkin N + connected to DSL Main House
2. (1) LINKSYS WIRELESS-G RANGE EXPANDER Main House (35’’ from Belkin to repeat)
3. (1) LINKSYS WIRELESS-G RANGE EXPANDER Garage (350’ to 400’ from expand to expand)

The Belkin is set to 802.11G 802.11b
Chan 11
Exten Chan 7
Bandwidth 20/40
Protected Mode Off.
Security is OFF