Ok, finally i have figured out the problem and i feel bad that i didn't get it from the beginning -.- lol
Anyway, the problem was simpily when i unplug the router from the power source, the repeater can't recinfigure itself automatically and i have to reconfigure it again manually so i have to make sure that the router is NEVER unplug or shut off. However, sometime i need to close the internet for a while for certian option configurations, now that is a problem since i have to configure my repeater every time my router is disconnected but the good news is that i have 2 routers and it will overcome the this problem, this is how i setup my home network.
1)First thing i will start wit the names of my 2 routers and repeater.
A) Speedtouch (main router)
B) Dlink Dir 655 (secondary router)
C) Airlive (repeater)
2) Setting up my home network.
My main router "Speedtouch" is connected to my secondary home telephone line and i connected "Speedtouch"to Dlink through an ethernet cable and whenever i need to close the internet i would close "Speedtouch" by switching it off either by unpluging from the power source or switching it off from the router's button on the back. this will cause Dlink to disconnect but will will not be "turned off". As a result, there is no need to reconfigur Airlive if Dlink has been disconnected without shutting it off.