Need Help with Coolpix S210

[2Monkeys]

I am not a photographer, but long to take great pictures. I bought this camera b/c my old one was not fast enough in between pictures. For the most part, this camera takes awesome pictures even at night. I cannot, however, take a decent picture at my kids' school!!! If we are in the cafeteria or the gym, the pictures come out dark and grainy. I have tried many different settings, and cannot get it right.

Any suggestions????