Panic Room-Safe Room-Bunker

I would like your input, on best ideas-constructiion of the above mentioned rooms.
We already have a "panic room" in our house, good location, hidden access etc (could use some improvements but does the job).
However, we also have a house, on a ranch in the boonies. The house is a stucco concrete combo with a tiled roof with cane under the tiles. Access to the rooms is via a spiral staircase. Door leading to the staircase is a semi armored door.Upstairs there are 3 rooms, two with their own bathrooms, one with a bathroom apart.
My question to you is; would I be better off reinforcing one of the rooms, which would mean reinforcing the roof section (if you remove the tiles, you can just cut through the cane) the walls, installing new type of door, possiblyventilatiion system, radio, separate generator etc. Or should we just construct a new room, separate from the other rooms, possibly downstairs. There are some unused structures around the house that have concrete walls, that possible could be used to begin constructing of the room.
Any other ideas-input would be appreciated.

Underground bunker is the best solution. Weigh cost verses uplifting exhisting above ground structures and supplies. I.E. you need shelter and supplies equally to survive. Forget only a 2 week supply,good start if you want to live 2 weeks. Ask yoursely this HOW LONG DO I WANT TO LIVE?
do not let me discourage you, if you have an above ground structure then definately start the uplift immedately AND start laying in SUPPLIES!
Remember Littlt By Little Does The Trick.
If I can be of further help please do not hessitate to ask.
Thank you for your time,

Just some links

www.bomb-shelter.net...
this one they build panic rooms also.
www.safehavenhomes.net...