Off the cuff...
Is it possible to add a second story? Yes. Is it practical? Probably not for structural & financial reasons. Odds are you could sell your current home and make out OK. Many many details needed to fill in the blanks.
I'll explain some more details on the nightmare of adding a second story and the future issues you may have. Just phone or email me direct via my website:
We will talk about the process, headaches, and the compromising the integrity of the structure as well as alterating the settlement of the home, resulting in future foundation issues, interior damage, etc.