Please help - using the TG582N as a wifi extender

[#1]

Just wondering if any one can help, i have an additional TG582N which i would like to put in the garage at the bottom of my garden to increase my wifi range, i currently have a powerline setup in the garage too, what is the easiest method and setup to enable the second TG582 to act as a wifi extender, is this possible?
Any help much appreciated, as im quite a beginner when it comes to networking.
Thanks in advance

[#2]

ive had a good search and found the following procedures is this correct.
1. Change Ip address to say 192.168.1.63
2. use same SSID and password as my primary router
3. Change Channel
4. Disable DHCP
is this correct?

[#3]

Are you running an ethernet cable to it or some other way of getting connectivity? (over power lines perhaps?)
Other stuff you said looks good to me.

[#4]

Yes i have a powerline setup, which i presume i just connect to one of the ports.

[#5]

I can't see any reason why it wouldn't work. Give it a go and see if you come into any problems. You seem to know what you're doing though. 

[#6]

This may help:
http://npr.me.uk/together.html ;