Good cameras?

Well here is my story. I've never really been into photography or anything of that nature. But my dad decodes about 2-3 years ago that he doesn't want to pay 800-1000 for a professional photographer to take pictures at my sisters Quincenera. So he goes out and buys a Sony DSLR a100.
I tried to learn what I could and took some pictures but I'd like to learn how to take better pictures with this thing.
I'm thinking of buying another camera and was wondering if this one is good or should I look into another camera. Any info would be great.