So I have just recently stared mining, I use Slush's pool, using an msi 7950 GPU at about 500 Mhash/s.  I noticed that on mining.bitcoin.cz the only number going up was my estimated reward, the unconfirmed reward, confirmed reward, and total reward all stay at zero.  Also, my estimated reward number only stays around 0.00001500 BTC.  Am I doing something wrong?  I also have it connected to a bitcoin wallet and is STILL synchronizing with network. PLEASE HELP  (Sorry if this is a stupid question, bitcoin is difficult to understand)