setting up wireless network access point

i have a talk talk 533 router and it will not reach the back of the house.
run a power line adapter to the back and set up my old Belkin n router as access point and all is well.

my questions our should they have different wireless channels each one to avoid problems

should there be a different said for each unit or use the same.

and if you did say different said would you still have everything on one network or by having set up access point with different said name you would make you would end up with two networks in your house.

a real novice so just trying to get everything running the easy-est way

thank you in advance for your help

I have mine set up with the same SSID but different channels. It's seamless.