I have a small house in which I need to do some repairs?

I want to tear out this front room what most people would consider a 15X10 cold trap. Inside this small room is the front entrance and the fireplace which consequently is leaking something very terrible - I need to put the fireplace in the original house part and I don't mind keeping it, it is a good fireplace but the roof leaks here very depressing. So my question is will this be hard to do? I need to keep in mind that the water heater is there and (although it doesn't work nothing in this front room does - there are dead electric lines). What are going to be my costs? I need to move the door into the house area, also I want to see if a fireplace shop will charge arms and legs to put in a fireplace pipe slash bricks that the fireplace can sit on. This will be a great house when finished I feel there is much potential. So to recap: tear out the front room which is completely useless, move the door into the house and then get a new location inside the small a frame house to put the fireplace. Potentially I would like to put a deck where the front room is.