Your best bet is to contact a local real estate agent to give you an approximate market value of your home and have them put it on the market. I'd suspect the value would be diminished due to the roofing and structural issues. Also, be sure to ask your agent about your disclosure obligations to future buyers. The agent should have a plan to market the home to buyers interested in the C2 zoned lot as well as investors/handyman buyers.
As far as buying another property, the agent should breakdown the costs of selling the home and give you an approximate dollar value you should expect to get at settlement. Keep in mind you'll also have additional costs associated with purchasing another home. Just be sure you'll have the funds to accommodate both the sale and purchase of each home.
I'd weigh the costs of sell/buy with the costs of making the repairs, if staying in the C2 zone is even remotely an option. Best of luck!