Louise
The shop that supplies the furniture is called Eco Muebles. It is in Los Gallardos.
I can't answer your other questions as we bought an extra sofa bed rather than swap the existing sofa.
To get to the shop, you go down to the bottom roundabout & turn right towards Consum. Then just keep going straight across all the roundabouts & the just stay on the main road. After about 16km from the last roundabout you come to a T junction. Turn left & the shop is a couple of hundred yards on the right.
If you get as far as the motorway roundabout, you have gone too far.
Noreen