my software update is slow but my wifi is fast

Hi ...

My name is Nesh. I am using a MacBook Pro (Retina, 13-inch, Late 2013). Currently i am facing a problems with it. When i try to update my operating system from Yosemite to Al Capitan, even updating any apps from the app store, its sluggishly slow with my network speed (data in) to hit an average 100kbps, but then again my wifi seems to be fast. my network speed( data in) seems to hit an average 700kbps when i'm using the web browser, even any apps which connects to the internet. My only issue is with the app store..
pls help me guys..