extending wire on wireless router to improve signal?

[t-maxxracer32]

the title sais it all.. my freind knows that i can solder and mess around with electrical components so he asked me if he could extend his wire on his wireless router to improve his signal. hes living in his parents side house and it wont reach all the way to the house

anyways if you cannot extend the wiring is there anything else he can do? he said the router cost him 110 so its gotta be somewhat decent.

thanks for any help