[Help] Building a Separate Bedroom

Hi! Ask lang po ako ng help kung magkano kaya magagastos sa pagpapagawa ng separate bedroom from ground up? And kung ano magandang gawin, very new lang din kasi ako sa mga ganitong bagay. Since may dalawang wall na po (see photos), ok lang ba na yun na rin yung wall ng bedroom para makatipid? Thanks in advanced :D

Dimensions:
4.86m x 4.32m (15.9449 ft x 14.1732 ft)

Photos:
Image may be NSFW.
Clik here to view.
Image may be NSFW.
Clik here to view.
Image may be NSFW.
Clik here to view.