If you mined at p2pool.org, the Bitcoins you've received for mining should be in your wallet already.
Maybe you should start with
1. move this thread to Bitcoin mining
2. show us the command line / .bat file / .. you used for mining or, even better, check if the bitcoin address from there is yours.
3. maybe state what mining hardware you use and for how long, or check the "stats" from
http://p2pool.org/stats/miner.php for your Bitcoin address to see if you did actually earn anything.
If the address is yours and you have funds there, then we can go further with converting into fiat money.