Hello Chrissy! You should check with a local contractor and local zoning laws to see what you can do! It will give you an idea of your options, and a estimate of cost. You will have to consider a foundation, plumbing, electricity along with the addition cost.
Call a professional to discuss different ways and designs. Get three bids. A person needs to be able to do carpentry, plumbing, hang drywall....
Thank you so much!