I honestly wouldn't worry too much about the OG of a posted extract brew. 1.053 seems perfectly fine to me. Punch everything into hopville (I guess its brewtoad now) and it will most likely come close to that.
Not sure what you are asking with number 2? Do you mean what to use to carb? Any sugar source will work as long as its not barley, rye, wheat, etc based. Plain old table sugar works fine for me. 4-5oz disolved in water per 5 gallon batch. There are plenty of carb calculators out there. I use brewzr on my phone for simple stuff.