I'm curious, may i ask a personal question and enquire how much your house was worth?
How much do you intend to pay developers that work on your project and what is the timeframe? -- I'm genuinely interested in that figure.
A game of this kind of scope would require tens to hundreds of millions of dollars to develop, it is a combination of google earth and GTA, both of which have hundreds of millions of dollars of development and millions of man hours sunk into them.
Unless you're selling a mansion, i think you may need further financing to see this through to the end.