Opinions on what to do with buying a house

Hello everyone!

We are in the process of looking for a new home and selling our town home. We have been out searching homes and tonight came across a bank owned home. It is everything we have been looking for in our searches.

Here is what we found when we looked at it. It needs all new carpet and paint. Not bad we can do that. They gutted some of the stuff, sure fine it can be replaced. The basement has been framed in! Great! Now the one bad thing we noticed is it has a 4 season room attached to one side of the house. It is sinking badly in 1 corner. I would say that corner has dropped about 1-2 inches. It is obvious in the trim and the window that is in that area.

That is the one thing that scares us the most about this house. I know it can be jacked up and fixed, but we have no idea who to contact or how about we find out how bad it really is! Do we need a structural engineer? Soil expert to find out why it sank. General builder to just lift it and pour a new footing? What steps do we do to find out about this?