Exterior is stucco, beams are wood. 

Any advice on what my first steps should be? Am

@Randy Smith usually a structural engineer is used to look at a main beam, basement wall, or a combination of joists that are suspect.There is almost always a solution to rebuild or salvage any of the above before a tear down makes more sense numbers wise.Do you have pricing on repairing whatever the issue is?

i was quoted 2500 to add on central air for a 1100 to 1200 sq ft house from Beam in pitcairn.  

@Steven BarrosDustin Beam

Looking at the pics, I'm surprised you would need a steel beam.  

If the load is too much for a 10' span with cheaper material, your options would be to run wood/metal the length of it to add support (joining to another load bearing wall assuming there is one) or to add a support beam in the middle.

Roof Repairs can easily become your most expensive part of the project, what happens if you have to replace some beams?  

1: The house had really appreciated since I purchased it (not a good reason), 2: The neighborhood might be transitioning to being a better area, though it is one of the lower grade neighborhoods in this city( a Toss-up), 3:The house has a big problem- 1 bed 2 baths on the main floor and 2 beds in a basement with 6 ft 2 inch ceilings and a beam down the middle.

I've worked with Kris as recommended above and Matt Beam for everything real estate.