Can I fix mold infestation of around 10 square feet, or do I need pro?
I agree the leak must be fixed first. Hydrogen peroxide is an excellent mold killer. Saturate any areas with a 3% or less solution (test the carpet for color fastness). Hydrogen peroxide will kill the mold and other organics with out the smell of chlorine. If you get a stronger solution of hydrogen peroxide always add the hydrogen peroxide to water not water to the hydrogen peroxide to prevent a bad reaction.  This can be done by a home owner and is easy works quickly. 1 application will usually kill even the toughest gunkies but a second may be needed.