How much would it cost to finish this basement?

the basement at my moms house flooded recently, there was a problem with the septic system..they completely fixed the problem and got the basement sanitized but the drywall had to be torn out and carpets as well. We are thinking about moving in when she moves out and would like to know how much it would cost to get new carpets and drywall...also, i know this is a silly question but doesnt something go on top of drywall? we arent very handy and may hire someone but i would still like to know how much it would cost b4 making any decisions. thanks! the basement is about 700 sf