1999 Buick lasabra gas leak found

I'm 63 year old I have been with no car and someone loaned me $1800 to get one. I've been looking over a month. Bought a one owner car 1999 Buick lasabra. It was real nice rode good engine clean and got it home and it has a slow leak in a tire and a big gas Leak. It was a as is what can I do.?