2004 Pontiac Grand Am

I just bought this car about a month and a half ago.
First I had trouble with the radiator. It would heat
up to almost in the red after driving about 5 miles.  
We kept putting water in the overflow. My husband
put some kind of sealent in it and it was fine for a
few days. Yesterday I had to go to the VA for an
appointment. After traveling for around 28 miles, I
stopped at a light and the car died at the light. It
would not turn over at all. I ended up calling a tow
truck to get home. I'm disappounted with Utahns.
Not one person stopped to help. When I got the car
back home, my husband charged the car. I took the
car to AutoZone, they tested the battery and the
alternator. The alternator was good but the battery
wasn't. I bought a new battery, it started up but it
seemed sluggish. I got home stopped then tried to
start it again. It would not start. I don't know what
else to do. Can anyone help? Besides telling me I'm
an idiot for buying a car for which I can't drive. I'm
a 62 year old woman you can call disappointed or
frustrated.