There are a few other reasons that the house may not be level. You didn't mention in what part of New Orleans this home is located. Some areas (Lakeview , Gentilly, and New Orleans East for example) many homes experience a foundation shift as these area required a lot of fill when they were developed years ago. Smart homeowners have loads of dirt delivered every couple of years to shore up the foundations in which case, the cost is minimal. If the foundation has shifted severely, there are shoring companies that will drive a more permanent foundation (pilings) underneatht teh existing structure. This can be quite costly, but will salvage the home. The reputable companies offer a lifetime warranty. Other homes are not level due to shoddy workmanship in which case you have a serious problem on your hands that may not be remedied through shoring.
If you are dead set on this particular home, your best bet is to hire a licensed home inspector who has experience with foundation issues. Your buyer's agent should be able to refer you to a reputable inspector and shoring company. If he cannot do so, don't hesitate to contact me.
Yup...there either is, was or will be termites under this portion of the house.
Look at the corners..are the gutters in decent condition? How close are the trees? How old is the house?
Sounds like you need a Buyer's Agent with construction experience. Call me if you are not already represented...and no, the Listing agent does not represent you, otherwise you would not be asking these questions...be cautious, careful and listen...to yourself mostly, for if your gut feelings think something could be wrong, it probably is... so reduce your risk and find a qualified person to help you.