Modifying basement in Medford to claim it as square footage?

[Rachel Feng]

Hi! I am thinking about doing some work in the basement in order to create extra sqft from basement. Right now the room is finished and it appears that the room has enough height. There is one exit (door) going out to the yard. It looks like I will need another bigger window for the second exit. I was wondering what's the ballpark number to make a bigger window in the picture attached. What kind of contractor will I need for this kind of project? GC? What is the cheapest option to install some sort of heating system in the basement that is separate from the house (e.g., electrical)? Any comments will be very much appreciated!