Problem using gateway as a repeater

So I recently moved again and I won't get my crappy adsl connection turned on until 20 days. However my friend lives right across the street and he offered to share his connection. Running a cable would be a bit problematic but using my old gateway as a repeater could work. He got a garage "in the middle of the street" (difficult to explain) however the gateway is placed well within his WiFi. 

The gateway is a Netgear DGN2200. I have went into the settings and enabled wireless repeating function and then I entered his gateways wireless MAC address into my gateway(now a repeater). However as soon as I do this I cannot access my gateways settings anymore and I have to reset it's settings. I have tried both the MAC address for the WiFi and the LAN but I get the same problem. I also have to enter a new ip address for my repeater and I wonder if I can enter whatever or should it be something special?

Anyone know something I can try? 

 

Ive used the wireless repeater functions before, and I must say they really stink. Maybe try DD-WRT or OpenWRT?

You may be losing access to your gateway because of IP conflicts. Try changing the address range of your router to a different subnet than your friend's, if it isn't already. Also try turning off DHCP, it may be a case of fighting DHCP servers.