can not download the updates for OS X

hi all,

please help me. i am not able to download the updates from app store.

it's showing 2 updates for my system.But as i start downloading it works fine for a while and after that the estimated time remaining just goes up & up and finally it stops downloading. It stops after downloading about 300 MB/2.64 GB or so.

please help. Really worried about my macbook pro.

Thanks.