what kind of wire to use and motherboard laptop replacement

I modded my Asus G53SX in an odd fashion. I cut a hole to the right of the power jack and inserted a new and better jack than the stock one that broke on me. But in order for the new jack too receive power I soldered the inner wire of an old power cord to the correct places. But this was only a temp fix since the wire is so bulky. What is a recommended type of wire to use? And unrelating to the wire, is there anything I need to know about replacing the motherboard? Like on removing the processor and replacing it in a new motherboard?

 

Are you able to post a picture of the power socket and motherboard? I'm not sure I fully understand the current setup, so a picture would help . Ideally, you'd be able to replace it with a like-for-like surface mount connector.

 

Well not yet for the picture, but essentially I just need a wire that will carry sufficient current