Reduce my carbon footprint

I own my own courier business that did not do well last year so I do not have the capital to cover this need I currently have. I have gotten a current contract serving people and medical agencies with courier needs and I want to add a Prius to my fleet so I can get better gas mileage and reduce my emissions. I travel over 350 miles a day on this new delivery route in a minivan. This new route and contract is my longest route and I do not need that much space or to produce that much pollution. The $5500.00 would allow me to improve my current fleet and, through an auto loan, replace one of my current gas-guzzling vans with a more efficient used Prius.