well u need to have the following devices to setup a HD streaming.
either one of the HD media player like WD live tv 2,Asus O!Play,popcorn hour(not avialable in india).
if u want to stream over ethernet cable then WD live tv or asus o play will do.
if u want wifi HD media player. then u need to spend more, and as far i know the best brand for wifi HD player is popcorn hour, but thats not available in india.
it varies from 10,000 to 20,000 Rs. but it can play almost every audio/video format
www.popcornhour.com.
and u need to have a wifi router with high range (typically comes with N series).
brands are D-link,Belkin,linksys,buffalo.
and the setup is easy.
first connect u r modems ethernet out to wifi router,then do setup
Then connect a ethernet cable from router to HD media player,
or if u buy wifi HD media player. connect from wifi HD Player to u r wifi router.
see the setup instructions provided by the vendor, as it varies from vendor to vendor