Check the Home >Painting link right below your question - lots of pricing and detailed comments on both interior and exterior painting there. Filling and sanding nail holes first (presume you mean on wood) probably about additional $100-200 depending on how much wood you have, assuming normal amount for a normal size house - obviously can run $1000 plus for a mansion with wood panelling.
For new construction, can run from $2000 for zero-prep spraying before any finish details, trim, cabinets, flooring etc are in, to as much as $25,000 for a 4000 SF home with two coats, separate treatment on alll windows and doors, base and crown molding, etc. Common number for finished new construction (painting after GC is out of there, so trim all in, etc would probably be in the $8000-10,000 range.
Here is one contractors web page that gives you a breakdown by room rather than square footage, which might help give you an idea, especially as square foot estimates tend to get out of whack on the high side when you doing the entire interior at one time.
One other thing - as about winter discount - many contractors give 25-50% discount on labor in winter, to keep their crews on board so they have experienced people they can trust when the spring remodel season and the summer outside painting seasons arrive.