Concrete

I have an open porch 12x10 (120 sq ft) concrete slab in my backyard patio. I would like to add about 60 sq ft more concrete add-on to it sideways (standard broom-finish). Alternatively, I was also thinking about perhaps adding 1/4" or 1/2" of stamped concrete overlay on the existing 120sq ft slab and the additional 60 sq ft add-on. I would appreciate if you could let me know the approx. adder for this stamped concrete option. For budget purpose, I would like to go with a simple design / single color for now. Lastly, I would like to install a 18x10 sq ft aluminum solid cover. This would be a basic slope cover with drains - nothing too fancy. Perhaps one fan and white paint with aluminum columns (up to 20lbs live load).