2007 Mazda 3 could you please help me?

Engine Mechanical problem
2007 Mazda 3 4 cyl Automatic 27,000 miles

Im a young teenage girl that knows hardly anything about cars! I have had my 07 mazda 3 for almost 5 months now, I bought the car with 13,000 miles on it, now it has doubled. I drive 60 miles (sometimes more) atleast 6 days per week.
I had drove the car to work thursday night, then drove it back home from work friday morning and everything was fine. About 2-3 hours later I had to run to town and pay bills, and I noticed my engine light was on (it didnt say check engine, it just showed the symbol of an engine). And of course this scares me to death because I had no idea what could have caused this. I took the car to auto zone and they hooked the machine up to it and the codes read: P2187 & P0443. The young lady that did this for me said it was the gas cap, so I took it off and put it on 2 times, the light was still on. She said I was low on gas, so I went and filled my gas tank up with 89 grade gas, that didnt help either. I called the dealership where I bought the car (which wasnt a mazda dealership) and the guy that helped me said he didnt have the tools to look at it, so I should take it to another place that is atleast an hour away from my house. He said it should be ok to drive, its probably nothing. So I drive the car all weekend long and everything seemed fine even though the light was still on.
Today is now Sunday, I was headed to work and I stopped at a drive thru window, and my car went dead. It has never done this before.
I have a 50,000 mile warranty, so im wondering if I take this car back to where I got it from even though its not a mazda dealership, will the warranty cove this?